# If cos(t)=(-7/8) where pi

4,795 questions
1. ## TRIG!

Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6 x=1 - (3/4)sin^2 2x work on one side only! Responses Trig please help! - Reiny, Monday, February 23, 2009 at 4:27pm LS looks like the sum of cubes sin^6 x + cos^6 x = (sin^2x)^3 +

asked by hayden on February 23, 2009
2. ## pre-cal

Simplify the given expression........? (2sin2x)(cos6x) sin 2x and cos 6x can be expressed as a series of terms that involve sin x or cos x only, but the end result is not a simplification. sin 2x = 2 sinx cosx cos 6x = 32 cos^6 x -48 cos^4 x + 18 cos^2 x -

asked by ethan on May 17, 2007
3. ## math

Determine exact value of cos(cos^-1(19 pi)). is this the cos (a+b)= cos a cos b- sina sin b? or is it something different. When plugging it in the calculator, do we enter it with cos and then the (cos^-1(19 pi)).

asked by Anonymous on April 14, 2012
4. ## math

Find the exact value of cos 300 degrees. thanks guys cos 300 = 1/2 = 0.500 how do you know? I am supposed to show my work. You ought to know the rule on 30-60-90 triangles. If the hyp is 2, the shorter side is 1, and the longer side is sqrt3. what does

asked by Bill on June 2, 2007
5. ## Precalculus

Solve Cos^2(x)+cos(x)=cos(2x). Give exact answers within the interval [0,2π) Ive got the equation down to -cos^2(x)+cos(x)+1=0 or and it can be simplified too sin^2(x)+cos(x)=0 If you could tell me where to go from either of these two, it would be great

asked by Josh on February 23, 2012
6. ## maths

Find the roots of z^6 + 1 and hence resolve z^6 + 1into read quadratic factors; deduce that cos3x = 4[cos(x) -cos(pi/6)][(cos(x) -cos(pi/2)][(cos(x) -cos(5pi/6)]

asked by jake on November 10, 2008
7. ## maths

Find the roots of z^6 + 1 and hence resolve z^6 + 1into read quadratic factors; deduce that cos3x = 4[cos(x) -cos(pi/6)][(cos(x) -cos(pi/2)][(cos(x) -cos(5pi/6)]

asked by jake on November 10, 2008
8. ## Calc.

Differentiate. y= (cos x)^x u= cos x du= -sin x dx ln y = ln(cos x)^x ln y = x ln(cos x) (dy/dx)/(y)= ln(cos x) (dy/dx)= y ln(cos x) = (cos x)^x * (ln cos x) (dx/du)= x(cos x)^(x-1) * (-sin x) = - x sin(x)cos^(x-1)(x) (dy/dx)-(dx/du)=

asked by Chelsea on March 9, 2011
9. ## calculus

Differentiate. y= (cos x)^x u= cos x du= -sin x dx ln y = ln(cos x)^x ln y = x ln(cos x) (dy/dx)/(y)= ln(cos x) (dy/dx)= y ln(cos x) = (cos x)^x * (ln cos x) (dx/du)= x(cos x)^(x-1) * (-sin x) = - x sin(x)cos^(x-1)(x) (dy/dx)-(dx/du)=

asked by Chelsea on March 10, 2011
10. ## Math - Solving Trig Equations

What am I doing wrong? Equation: sin2x = 2cos2x Answers: 90 and 270 .... My Work: 2sin(x)cos(x) = 2cos(2x) sin(x) cos(x) = cos(2x) sin(x) cos(x) = 2cos^2(x) - 1 cos(x) (+/-)\sqrt{1 - cos^2(x)} = 2cos^2(x) - 1 cos^2(x)(1 - cos^2(x)) = 4cos^4(x) - 4cos^2(x)

asked by Anonymous on November 24, 2007
11. ## Trigonometry

There is an arbitrary triangle with angles A, B, and C and sides of lengths a, b, and c. Angle A is opposite side a. How do I get the formulas: b * cos C + c * cos B = a c * cos A + a * cos C = b a * cos B + b * cos A = c Are these standard trig formulas?

asked by mathstudent on December 15, 2006
12. ## trig

Reduce the following to the sine or cosine of one angle: (i) sin145*cos75 - cos145*sin75 (ii) cos35*cos15 - sin35*sin15 Use the formulae: sin(a+b)= sin(a) cos(b) + cos(a)sin(b) and cos(a+b)= cos(a)cos(b) - sin(a)sin)(b) (1)The quantity = sin(145-75) = sin

asked by Paul C on November 26, 2006
13. ## Mathematics - Trigonometric Identities - Reiny

Mathematics - Trigonometric Identities - Reiny, Friday, November 9, 2007 at 10:30pm (sinx - 1 -cos^2x) (sinx + 1 - cos^2x) should have been (sinx - 1 + cos^2x) (sinx + 1 - cos^2x) and then the next line should be sin^2x + sinx - cos^2xsinx - sinx - 1 +

asked by Anonymous on November 10, 2007
14. ## calculus

pleaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaasw help can you pleaaaaase help me find the area between y=cos(4x) and y=1-cos(4x) 0

asked by aymal on May 2, 2010
15. ## Trigonometry

Write equivalent equations in the form of inverse functions for a.)x=y+cos è b.)cosy=x^2 (can you show how you would solve) a.) x= y+ cos è cos è = x-y theta = cos^-1(x-y) b.) cosy=x^2 cos(y) = x^2 y = Cos^-1(x^2)

asked by anon on March 3, 2011
16. ## Trig. Law of Cosines

Show that any triangle with standard labeling... a^2+b^2+c^2/2abc = cos(alpha)/a + cos(beta)/b + cos(gamma)/c I don't get it. Can someone please help me. Start here with the law of cosines: a^2 = b^2 + c^2 -2bc Cos A b^2 = a^2 + c^2 -2ac Cos B c^2 = a^2 +

asked by ashley on December 12, 2006
17. ## tigonometry

expres the following as sums and differences of sines or cosines cos8t * sin2t sin(a+b) = sin(a)cos(b) + cos(a)sin(b) replacing by by -b and using that cos(-b)= cos(b) sin(-b)= -sin(b) gives: sin(a-b) = sin(a)cos(b) - cos(a)sin(b) Add the two equations:

asked by Pablo on November 26, 2006
18. ## algebra

Can someone please help me do this problem? That would be great! Simplify the expression: sin theta + cos theta * cot theta I'll use A for theta. Cot A = sin A / cos A Therefore: sin A + (cos A * sin A / cos A) = sin A + sin A = 2 sin A I hope this will

asked by Valerie on February 18, 2007
19. ## Precal

I do not understand how to do this problem ((sin^3 A + cos^3 A)/(sin A + cos A) ) = 1 - sin A cos A note that all the trig terms are closed right after there A's example sin A cos A = sin (A) cos (A) I wrote it out like this 0 = - sin^6 A - cos^6 A +

asked by Joe on January 14, 2010
20. ## Algebra

Write an equation for the translation of the function. y = cos x; translated 6 units up A. y = cos x- ­ 6 B. y = cos(x + 6) C. y = cos x + 6 D. y = cos(x ­ 6) I think its B or c..

asked by Veronika on February 23, 2016
21. ## Pre-Cal (Trig) Help?

The following relationship is known to be true for two angles A and B: cos(A)cos(B)-sin(A)sin(B)=0.957269 Express A in terms of the angle B. Work in degrees and report numeric values accurate to 2 decimal places. So I'm pretty lost on how to even begin

asked by Giovanni on May 6, 2016
22. ## trig

Show that 1-cos2A/Cos^2*A = tan^2*A 1-cos2A/Cos^2*A = [Cos^2(A) - Cos(2A)]/Cos^2(A). Substitute: Cos(2A) = 2Cos^2(A) - 1: [1 - Cos^2(A)]/Cos^2(A)= Sin^2(A)/Cos^2(A) = tan^2(A)

asked by Paul C on November 26, 2006
23. ## Trig Help!

Question: Trying to find cos π/12, if cos π/6 = square root 3 over 2, how to find cos π/12 using DOUBLE angle formula? This is what I got so far.. cos 2(π/6) = cos (π/6 + π/6) = (cos π/6)(cos π/6) - (sin π/6)(sin π/6) = cos^2 π/6 - sin^2 π/6 Is

asked by Anonymous on April 27, 2012
24. ## math

if cos(B-C)+cos(C-A)+cos(A-B)=-3/2 then prove that cosA+cosB+cosC=O and sinA+sinB+sinC=O after that prove that cos(B-C)=cos(C-A)=cos(A-B)=-1/2

asked by Binoy kumar mahato on October 6, 2017
25. ## Mathematics - Trigonometric Identities

Let y represent theta Prove: 1 + 1/tan^2y = 1/sin^2y My Answer: LS: = 1 + 1/tan^2y = (sin^2y + cos^2y) + 1 /(sin^2y/cos^2y) = (sin^2y + cos^2y) + 1 x (cos^2y/sin^2y) = (sin^2y + cos^2y) + (sin^2y + cos^2y) (cos^2y/sin^2y) = (sin^2y + cos^2y) + (sin^2y +

asked by Anonymous on November 8, 2007
26. ## MATH

Hi, I really need help with these questions. I did some of them halfway, but then I got stuck. Would you please help me? Thank you so much. Prove the identity.... 1. sec x + tan x(1-sin x/cos x)=1 1/cos x + sin x/cos x(cos^2 x/cos x)=1 1+sin x/cos

asked by LIZZIE010 on January 2, 2014
27. ## Studying for Pre Cal exam

Find the fourth roots of − 1/2 + (square root)3/2 i Write the roots in trigonometric form. A - w 1=cos(35°)+isin(35°) w2 =cos(125°)+isin(125°) w3 =cos(215°)+isin(215°) w4 =cos(305°)+isin(305°) B - w1 =cos(40°)+isin(40°) w2

asked by Lottie on July 13, 2016
28. ## Math - Solving Trig Equations

Solve each equation for o is less than and/or equal to theta is less than and/or equal to 360 -- sin^2x = 1 = cos^2x -- Work: cos^2x - cos^2x = 0 0 = 0 -- Textbook Answers: 90 and 270 -- Btw, how would you isolate for cos^2x = 0? Would it be... x = cos^-1

asked by Anonymous on November 24, 2007
29. ## Math - Solving for Trig Equations

Solve the following equation for 0 less than and/or equal to "x" less than and/or equal to 360 -- cos^2x - 1 = sin^2x -- Attempt: cos^2x - 1 - sin^2x = 0 cos^2x - 1 - (1 - cos^2x) = 0 cos^2x - 1 - 1 + cos^2x = 0 2cos^2x - 2 = 0 (2cos^2x/2)= (-2/2) cos^2x =

asked by Anonymous on November 22, 2007
30. ## Math

Explain how to do this with steps please. 1. Simplify cos(x-y)+cos(x+y)/cosx I did some of these so far, don't know if it is correct. Formula: cosxcosy= cos(x+y)+cos(x-y)/2 cos(x-y)+cos(x+y)/cosx =cosxcosy/2cosx

asked by Jake on January 26, 2012
31. ## Math

Solve this equation algebraically: (1-sin x)/cos x = cos x/(1+sin x) --- I know the answer is an identity, and when graphed, it looks like cot x. I just don't know how to get there. I tried multiplying each side by its conjugate, but I still feel stuck.

asked by Momo on October 18, 2009
32. ## Math, derivatives

Let g(x) = sin (cos x^3) Find g ' (x): The choices are a) -3x^2sinx^3cos(cos x^3) b) -3x^2sinx^3sin(cos x^3) c) -3x^2cosx^3sin(cos x^3) d) 3x^2sin^2(cos x^3) I'm not exactly sure where I should start. Should I begin with d/dx of sin? Or do the inside

asked by Marissa on May 11, 2008

ok, i tried to do what you told me but i cant solve it for c because they cancel each others out! the integral for the first one i got is [sin(c)cos(x)-cos(c)sin(x)+sin(x)+c] and the integral for the 2nd one i got is [-sin(c)cos(x)+cos(c)sin(x)-sin(x)+c] I

asked by K on November 29, 2010
34. ## Calculus

which of the following integrals results from making the substitution u=x^3 in orer to find (squiggly vertical line)x^2cos(x^3)dx ~cos u du ~u^2 cos u du ~u^(2/3) cos u du1/3 os u du ~3 cos u du

asked by Ken on May 11, 2012

Use the fundamental identities to simplify the expression. tan^2 Q / sec^2 Q sin^2/cos^2 / 1/cos^2 = sin^2 / cos^2 times cos^2 / 1 = The cos^2 cancels out so sin^2 is left. Is this correct?

asked by Hannah on March 5, 2010
36. ## trigonomentry out of ideal help ah!crying

compute.. Cos(1degree)+cos(3degree)+cos(5degree)+...+Cos(179degree) plz show working even an hint can,t help me.Have been do maths alday my brain is fried..Ah thanks

asked by david on April 1, 2016
37. ## calc.- trig substitution

s- integral s 1/ [ (x^4) sq.rt(x^2+9)] i know x=3tanx sq.rt(x^2+9)= 3 secx dx= 3/[cos^2(x)] so far i know: = 1/ (3tan^4(x)) 3secx cos^2(x)) dx =1/ 81 [ (sin^4 (x)/cos^4 (x)) (1/cosx) (cos^2(x))] then i'm not really sure what to do next

asked by christine on February 26, 2007
38. ## trig

it says to verify the following identity, working only on one side: cotx+tanx=cscx*secx Work the left side. cot x + tan x = cos x/sin x + sin x/cos x = (cos^2 x +sin^2x)/(sin x cos x) = 1/(sin x cos x) = 1/sin x * 1/cos x You're almost there. thanks so

asked by Devon on May 7, 2007
39. ## Trigonometry - LONESTAR

Simplifying steps without using the calculator for: tan(cos^-1(-1/10)) cos(sin^−1(1/x)) Assume x is positive tan(cos^−1(12/13)) cos^−1(cos 150°) This is pretty much the entire section we are doing. My teacher is a robot and has us self teach

asked by Angels on March 3, 2014
40. ## trig

2sin(x)cos(x)+cos(x)=0 I'm looking for exact value solutions in [0, 3π] So I need to find general solutions to solve the equation. But do I eliminate cos(x), like this... 2sin(x)cos(x)+cos(x)=0 2sin(x)cos(x)= -cos(x) 2sin(x) = -1 sin(x) = -1/2 at 4pi/3

asked by Alex on March 23, 2008
41. ## Trig

Given: cos u = 3/5; 0 < u < pi/2 cos v = 5/13; 3pi/2 < v < 2pi Find: sin (v + u) cos (v - u) tan (v + u) First compute or list the cosine and sine of both u and v. Then use the combination rules sin (v + u) = sin u cos v + cos v sin u. cos (v - u) = cos u

asked by Nan on December 29, 2006
42. ## Trigonometry (repost Reiny)

at 1:35am I posted ; Write equivalent equations in the form of inverse functions for a.)x=y+cos theta b.)cosy=x^2 my answers were a.) x= y+ cos theta cos theta = x-y theta = cos^-1(x-y) b.) cosy=x^2 cos(y) = x^2 y = Cos^-1(x^2) your post confused me a

asked by anon on March 3, 2011
43. ## precalculus

I don't understand this problem: (Tanө + cos ө)/ (sec ө + cot ө) so I start off like this: ={(sinө / cos ө)+cosө}{cos ө + (sinө/cosө)} =[(sin ө +cos^2ө) (cos^2ө +sin ө)]/ cos ө but what comes next?

asked by allison on February 22, 2009
44. ## Trig/Precalc

So I have two questions that have been puzzling me for quite some time and would really appreciate any help with either of them! (a) There are four positive intergers a, b, c, and d such that 4cos(x)cos(2x)cos(4x)=cos(ax)+cos(bx)+cos(cx)+cos(dx) for all

asked by majorbill on January 4, 2015
45. ## Math

Explain how to do this with steps please. 1. Simplify cos(x-y)+cos(x+y)/cosx Formula: cosxcosy= cos(x+y)+cos(x-y)/2 cos(x-y)+cos(x+y)/cosx =cosxcosy/2cosx

asked by Jake on January 26, 2012
46. ## Math

Find the exact value of cos 1 degree + cos 2 degrees + cos 3 degrees + ... + cos 357 + cos 358 degrees + cos 359 degrees.

asked by EC on October 24, 2016

I posted before ; Write equivalent equations in the form of inverse functions for a.)x=y+cos theta b.)cosy=x^2 my answers were a.) x= y+ cos theta cos theta = x-y theta = cos^-1(x-y) b.) cosy=x^2 cos(y) = x^2 y = Cos^-1(x^2) your post confused me a little.

asked by anon on March 4, 2011
48. ## trig

how would you verify this trig identity (1+cos(x) / 1-cos(x)) - (1-cos(x) / 1+cos(x)) = 4cot(x)csc(x) ? help please!

asked by amanda on June 25, 2008
49. ## math

Prove that for all real values of a, b, t (theta): (a * cos t + b * sin t)^2

asked by mathstudent on December 19, 2006
50. ## Math

Prove each identity: a) 1-cos^2x=tan^2xcos^2x b) cos^2x + 2sin^2x-1 = sin^2x I also tried a question on my own: tan^2x = (1 – cos^2x)/cos^2x R.S.= sin^2x/cos^2x I know that the Pythagorean for that is sin^2x + cos^2x That's all I could do.

asked by Kate on July 18, 2011
51. ## Math

Write the expression in terms of costheta and then simplify. cos^4theta - sin^4theta + sin^2theta Ans: cos^4 θ - 1 - cos^4 θ + 1 - cos^2 θ = -cos^2 θ

asked by Anonymous on June 2, 2015
52. ## Math

Eliminate the parameter and write the corresponding rectangular equation whose graph represents the curve. x = sec Q y = cos Q x^2 + y^2 = 1/cos^2 + sin^2/cos^2 = x^2(1 +sin^2) = x^2(2-cos^2) x^2(2-1/x^2) = 2x^2 - 1 x^2 - y^2 = 1 My teacher said to use

asked by Abbey on May 4, 2010
53. ## Calculus AP

Use the table of integrals to find int cos^4 3x dx I found the table: ∫cos^n u du = (1/n)cos^(n-1)u sinu + (n-1/n)∫sin^(n-2)u du = 1/4 cos^(4-1)u sinu + (4-1/4)∫sin^(4-2) u du so what i did the problem: let u=3x then du=3dx =1/4*1/3 cos^3u sinu +

asked by Vicky on September 20, 2012
54. ## Math (Trigonometry [Polar Form])

Let z be a complex number such that z = 2(cos 8∘ + i cos 82∘).Then z^5 can be expressed as r(sin α∘+ i cos α∘), where r is a real number and 0 ≤ α ≤ 90. What is the value of r+α? Hint to solve: Example Question: Let z be a complex number

asked by Shin on June 22, 2013
55. ## Calculus

Evaluate (Integral) sin 4x cos^2 4x dx. A. Cos^3(4x)/3 + C B. -Cos^3(4x)/3 + C C. Cos^3(4x)/12 + C D. -Cos^3(4x)/12 + C

asked by Cynthia on August 4, 2012
56. ## Calculus

what is the limit n to infinite of cos1*cos(1/2)*cos(1/4)*cos(1/8)*cos(1/16)*...*cos(1/2^n)

asked by CHRIS on December 19, 2013
57. ## Calculus

Evaluate the integral sin4x cos^2 4x dx A. cos^3 4x/3 +C B. - cos^3 4x/3 +C C. cos^3 4x/12 +C D. -cos^3 4x/12 +C

asked by Tracy on November 19, 2011
58. ## Calculus

Find F '(x) for F(x) = integral[x^3 to 1](cos(t^4)dt) a. cos(x^7) b. -cos(x^12) c. -3x^2cos(x^12) d. cos(1) - cos(x^12)

asked by Jimmy on May 16, 2018
59. ## Trigonometry

Please review and tell me if i did something wrong. Find the following functions correct to five decimal places: a. sin 22degrees 43' b. cos 44degrees 56' c. sin 49degrees 17' d. tan 11degrees 37' e. sin 79degrees 23'30' f. cot 19degrees 0' 25'' g. tan

asked by Anon on January 1, 2011
60. ## Math

Can someone please check my answers! 2. Find value of cos(255degrees)cos(105degrees) root3 - 2 / 4 3. cos(pi/12) - cos(5pi/12) Is it root3/4? 4. Use the appropriate sum-to-product formula to rewrite the expression sin6x - sin9x I don't really understand

asked by mysterychicken on June 3, 2013
61. ## precalc

Find the exact value of each expression, if it exists: the -1 are representing the inverse functions! (a) sin -1 (-√2/2) (b) cos−1 (−1) (c) sin( 􏰀sin−1 (π)􏰁) (d) cos−1􏰀(cos􏰀(−4π􏰁􏰁/ 3)) (e) tan−1 (tan(0.6)) (f) cos−1(

asked by help! on April 17, 2016
62. ## math

Can you please check my work. A particle is moving with the given data. Find the position of the particle. a(t) = cos(t) + sin(t) s(0) = 2 v(0) = 6 a(t) = cos(t) + sin(t) v(t) = sin(t) - cos(t) + C s(t) = -cos(t) - sin(t) + Cx + D 6 = v(0) = sin(0) -cos(0)

asked by Kay on June 23, 2011
63. ## math

How would you establish this identity: (1+sec(beta))/(sec(beta))=(sin^2(beta))/(1-cos(beta)) on the right, sin^2 = 1-cos^2, that factor to 1-cos * `1+cos, then the denominator makes the entire right side 1+cosB which is 1+1/sec which is 1/sec (sec+1) qed

asked by michelle on June 13, 2007
64. ## Calculus

how do you solve this trig identity? i don't get it at all! cos(a+b)cos(a-b)=cos^2a-cos^2b-1

asked by sakura on November 9, 2015
65. ## calc

Where do I start to prove this identity: sinx/cosx= 1-cos2x/sin2x please help!! Hint: Fractions are evil. Get rid of them. Well, cos2x = cos2x - sin2x, so 1-coscx = 1 - cos2x - sin2x = 1 - cos2x + sin2x You should be able to simplify this to 2*something

asked by maria on October 21, 2006
66. ## math

A trigonmetric polynomial of order n is t(x) = c0 + c1 * cos x + c2 * cos 2x + ... + cn * cos nx + d1 * sin x + d2 * sin 2x + ... + dn * sin nx The output vector space of such a function has the vector basis: { 1, cos x, cos 2x, ..., cos nx, sin x, sin 2x,

asked by mathstudent on January 16, 2008
67. ## Physics

What should be the angle between two vectors of magnitudes 3.20 and 5.70 units, so that their resultant has a magnitude of 6.10 units? Cos x = (b^2 + c^2 - a^2) / 2bc Cos x = (3.2^2 + 5.7^2 - 6.1^2) / (2 * 3.2 * 5.7) Cos x = 5.52/36.48 Cos x = 0.15 x =

asked by Jamie on May 25, 2009
68. ## PRECALC

solve the equation 1. cos(θ) − sin(θ) = 1 2.2 cos(θ) tan(θ) + tan(θ) = 1 + 2 cos(θ) 3. sin(θ) cos(3θ) + cos(θ) sin(3θ) = 0 4. sin(2θ) cos(θ) − cos(2θ) sin(θ) = 1/2 5. cos(2θ) + cos(θ) = 2 6. cos(2θ) + sin2(θ) = 0

asked by help! on April 26, 2016

What are the ratios for sin A and cos A? The diagram is not drawn to scale. Triangle Description- AB = 29 AC = 20 BC - 21 A. sin A = 20/29, cos A = 21/29 B. sin A = 21/29, cos A = 20/21 C. sin A = 21/29, cos A = 20/29****? D. sin A = 21/20, cos A = 20/21

asked by Battia Anne on June 7, 2016
70. ## Pre-Cal

1) Verify the identity cos^2 B - sin^2 B = 2 cos^2 B -1 I know that cos^2 B - sin^2 B = 2 cos^2 B -1 by the double angle formula but I do not know how to show this.

asked by Hannah on February 27, 2010
71. ## Precalculus

Use one of the identities cos(t + 2πk) = cos t or sin(t + 2πk) = sin t to evaluate each expression. (Enter your answers in exact form.) (a) sin(19π/4) (b) sin(−19π/4) (c) cos(11π) (d) cos(53π/4) (e) tan(−3π/4) (f) cos(π/4) (g) sec(π/6+ 2π)

asked by Kaleen on March 10, 2012
72. ## Math - Trigonometry

Let f(x) be a polynomial such that f(cos theta) = cos(4 theta) for all \theta. Find f(x). (This is essentially the same as finding cos(4 theta) in terms of cos theta; we structure the problem this way so that you can answer as a polynomial. Be sure to

asked by Sam on November 6, 2013
73. ## Pre-Calculus

I don't understand,please be clear! Prove that each equation is an identity. I tried to do the problems, but I am stuck. 1. cos^4 t-sin^4 t=1-2sin^2 t 2. 1/cos s= csc^2 s - csc s cot s 3. (cos x/ sec x -1)- (cos x/ tan^2x)=cot^2 x 4. sin^3 z cos^2 z= sin^3

asked by Anonymous on October 31, 2013
74. ## Trig

Find sin(s+t) and (s-t) if cos(s)= 1/5 and sin(t) = 3/5 and s and t are in quadrant 1. =Sin(s)cos(t) + Cos(s)Sin(t) =Sin(1/5)Cos(3/5) + Cos(-1/5)Sin(3/5) = 0.389418 Sin(s-t) =sin(s)cos(t) - cos(s)sin(t) =sin(-3/5)cos(1/5) - cos(1/5)sin(3/5) =Sin-3/5

asked by Sally on May 7, 2015
75. ## Math

cos(tan + cot) = csc only simplify one side to equal csc so far I got this far: [((cos)(sin))/(cos)] + [((cos)(cos))/(sin)] = csc I don't know what to do next

asked by Amy on March 18, 2011
76. ## Math

The graph of f(x), a trigonometric function, and the graph of g(x) = c intersect at n points over the interval 0

asked by Max on March 19, 2018
77. ## Trigonometry

Okay, I have been given a trigonometric equation to solve (sin^2(theta) + cos(theta) = 2). So far, I have been able to use the Pythagorean identity to get (-cos^2(theta) + cos(theta) - 1 = 0), which I then multiplied by -1 on both sides to get:

asked by Veronica on March 24, 2011

1.)Find dy/dx when y= Ln (sinh 2x) my answer >> 2coth 2x. 2.)Find dy/dx when sinh 3y=cos 2x A.-2 sin 2x B.-2 sin 2x / sinh 3y C.-2/3tan (2x/3y) D.-2sin2x / 3 cosh 3yz...>> my answer. 2).Find the derivative of y=cos(x^2) with respect to x. A.-sin (2x) B.-2x

asked by anon on March 6, 2011
79. ## Math Trig

13. What is the equation of a cosine function with amplitude 3, transition point (−1, 1), and period p? A. y = p cos [3(x − 1)] − 1 B. y = 3 cos [2(x − 1)] + 1 C. y = 3 cos [p (x + 1)] − 1 D. y = 3 cos [2(x + 1)] + 1 16. What is the transition

asked by yeahyeah on July 14, 2012
80. ## Calculus problem

Evaulate: integral 3x (sinx/cos^4x) dx I think it's sec3 x , but that from using a piece of software, so you'll have to verify that. Using uppercase 's' for the integral sign we have S 3sin(x)/cos4dx or S cos-4(x)*3sin(x)dx If you let u = cos(x) then du =

asked by Rain on October 16, 2006

y=3e^(2x)cos(2x-3) verify that d^2y/dx^2-4dy/dx+8y=0 plz help me i tried all i could but it become too complicated for me here set u=3e^(2x) v=cos(2x-3) du/dx=6e^(2x) i used chain rule dv/dx=-2sin(2x-3) dy/dx=-3e^(2x)sin(2x-3)+cos(2x-3)6e^(2x) d^2y/dx^2

asked by practising and need help on November 13, 2016
82. ## Math question - plz correct

Two airplanes leave an airport at the same time. One travels at 355km/h and the other at 450km/h. Two hrs later they are 800km apart. Find the angle between their courses. a^2 = b^2 + c^2 - 2bc Cos A 800^2= 450^2 + 355^2 - 2(450)(355) Cos A 640000= 202 500

asked by May on May 27, 2008
83. ## AP Calculus

Find the velocity, v(t), for an object moving along the x-axis if the acceleration, a(t), is a(t) = cos(t) - sin(t) and v(0) = 3 v(t) = sin(t) + cos(t) + 3 v(t) = sin(t) + cos(t) + 2 v(t) = sin(t) - cos(t) + 3 v(t) = sin(t) - cos(t) + 4

asked by Will on June 19, 2018
84. ## Calculus

Find the velocity, v(t), for an object moving along the x-axis if the acceleration, a(t), is a(t) = cos(t) − sin(t) and v(0) = 3. a) v(t) = sin(t) + cos(t) +3 b) v(t) = sin(t) + cos(t) +2 c) v(t) = sin(t) - cos(t) +3 d) v(t) = sin(t) - cos(t) +4

asked by Alice on January 26, 2019
85. ## Calculus

Find the velocity, v(t), for an object moving along the x-axis in the acceleration, a(t), is a(t)=cos(t)-sin(t) and v(0)=3 a) v(t)=sin(t) + cos(t) +3 b) v(t)=sin(t) + cos(t) +2 c) v(t)= sin(t) - cos(t) +3 d) v(t)= sin(t) - cos(t) +4

asked by Alice on January 25, 2019
86. ## Trigonometry

I need to prove that the following is true. Thanks. csc^2(A/2)=2secA/secA-1 Right Side=(2/cosA)/(1/cosA - 1) = (2/cosA)/[(1-cosA)/cosA] =2/cosA x (cosA)/(1-cosA) =2/(1-cosA) now recall cos 2X = cos^2 X - sin^2 X and we could say cos A = cos^2 A/2 - sin^2

asked by Dirk on April 17, 2007
87. ## calc

find the area between the x-axis and the graph of the given function over the given interval: y = sqrt(9-x^2) over [-3,3] you need to do integration from -3 to 3. First you find the anti-derivative when you find the anti-derivative you plug in -3 to the

asked by mikayla on April 18, 2007
88. ## Physics

A basketball player shoots a free throw at a 50 degree angle. Assume the ball is released at a height of 1.8 meters, the hoop is 3 meters off of the floor and 4.6 meters away from the shooter. With what velocity should the player release the ball to hit

asked by Taylor on September 27, 2015

How would I do this: -cos(90-x) I know you would use the compound angle formula and I know how to do it but when you have -cos do you replace the cos with the negative? so for example -cos90(-cosx) + sinx(sin90)

asked by Mandy on November 14, 2015
90. ## Trig

If cosx = 10/19 an pi < x < 2pi, find the exact value of cos x/2 Use the double angle formula. Cos 2Y= sin^2 Y - cos^2Y = 1-2Cos^2 Y. let y= x/2, and 2Y=x

asked by Ashley on April 14, 2007
91. ## Pre Calculus

Solve 2cos^2(2x)=1 I divided both sides by 2 and got this cos^2(2x)=1/2 But then I didn't know what to do after that... The part that has me stumped is that it's a cos^2(2x) not just a cos^2x. Any advice on what I should try next?

asked by Chris on May 8, 2013
92. ## Trig identity.

I need help with verifying these trig identities: 1) sin4x = 4sinxcos - 8sin^3 x cos x 2) cos3x = cos^3 x - 3sin^2 x cos x

asked by Jane on March 15, 2016
93. ## MATHEMATICS

evaluate :- lim (existing from n to infinity)1/n^2 [1/1+cos(pie/2n) +2/1+cos(2pie/2n) + 3/1+cos(3pie/2n)+......to n terms]

asked by PRERANA on May 22, 2011
94. ## Math

Trig Identity Prove: cos(x+y)cos(x-y)=cos^2(x)+cos^2(y)-1

asked by Halle on June 18, 2009
95. ## Trigonometry

What is cos (pi/2 - x) secx using the fundamental identities to simplify the expression. I think I have the right answer but I want to check to make sure. Well, cos (pi/2 - x) is something you should've seen already. It's just another name for sin(x).

asked by Rob on October 18, 2006
96. ## cosines

I don't know how to reverse cosine decimals into angles. Can you please explain and help me solve these . cos A= 0.28571428571 A= cos B= 0.66666666667 B= cos C= 0.5238089523

asked by Anon on February 27, 2011
97. ## Calculus

Let OP be any vector with direction angles theta, beta, and gama. Explain why cos^2theta + cos^2beta + cos^2gama = 1

asked by Ria on May 17, 2010
98. ## calculus

The limit represents the derivative of some function f at some number a. Select an appropriate f(x) and a. lim (cos(pi+h)+1)/h h->0 answers are f(x) = tan(x), a = pi f(x) = cos(x), a = pi/4 f(x) = cos(x), a = pi f(x) = sin(x), a = pi

asked by Anonymous on October 7, 2009
99. ## need help calculus plz plz-sir steve

if y=3e^(2x)cos(2x-3) verify that d^2y/dx^2-4dy/dx+8y=0 plz help me i tried all i could but it become too complicated for me here set u=3e^(2x) v=cos(2x-3) du/dx=6e^(2x) i used chain rule dv/dx=-2sin(2x-3) dy/dx=-3e^(2x)sin(2x-3)+cos(2x-3)6e^(2x) d^2y/dx^2

asked by practising and need help on November 13, 2016
100. ## Calculus

Integrate 1/sinx dx using the identity sinx=2(sin(x/2)cos(x/2)). I rewrote the integral to 1/2 ∫ 1/(sin(x/2)cos(x/2))dx, but I don't know how to continue. Thanks for the help. Calculus - Steve, Tuesday, January 12, 2016 at 12:45am 1/2 ∫