Approximate cos (2π/13) by using a linear approximation with f (x) =cos x. cos (2π/13)≈ f(a) + f ' (a)·h = c, what is h, a, and c? I'm having problems with this one please help
12,137 results
Trig
Find sin(s+t) and (st) 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(st) =sin(s)cos(t)  cos(s)sin(t) =sin(3/5)cos(1/5)  cos(1/5)sin(3/5) =Sin3/5

linear approximation
Approximate cos (2π/13) by using a linear approximation with f (x) =cos x. cos (2π/13)≈ f(a) + f ' (a)·h = c, what is h, a, and c? I'm having problems with this one please help

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

math
if cos(BC)+cos(CA)+cos(AB)=3/2 then prove that cosA+cosB+cosC=O and sinA+sinB+sinC=O after that prove that cos(BC)=cos(CA)=cos(AB)=1/2

Calculus 12th grade (double check my work please)
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

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)

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

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

selfstudy calculus
Sketch the curve with the given vector equation. Indicate with an arrow the direction in which t increases. r(t)=cos(t)I cos(t)j+sin(t)k I don't know what to do. I let x=cos(t), y=cos(t) and z= sin(t). Should I let t be any number and get the equal

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

another please help me check~calculus maths
y=3e^(2x)cos(2x3) verify that d^2y/dx^24dy/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(2x3) du/dx=6e^(2x) i used chain rule dv/dx=2sin(2x3) dy/dx=3e^(2x)sin(2x3)+cos(2x3)6e^(2x) d^2y/dx^2

PreCal (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

Calculus
Which of the following is the best linear approximation for f(x)=cos(x) near x= π/2 ? a) y= x  π/2 b) y= x + π/2 c) y= x + π/2 + 1 d) y= x  π/2 +1

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..

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

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

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)

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

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)]

Homework Help Calculus
Find the linear approximation L(x)of the function f(x)=cos(pi/(6)x) at the point x=1 and use it to estimate the value of cos(13pi/72). Here's what I did so far: L(x)=sqrt(3)/21/12pi(x1)+0((x1)^2) How do I find cos(13pi/72)

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(ab) = sin(a)cos(b)  cos(a)sin(b) Add the two equations:

math Trigonometry
If cos degree equals to 0.8641 What is Sin degree? I have no idea how to find this. Please help me. I got help from two people, but I'm not getting the answer and how they got the numbers either. Someone says: cos^2+sin^2=1 sinDegree=sqrt(1cos^2degree)

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 =

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

Calculus
Find the velocity, v(t), for an object moving along the xaxis 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

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)^(x1) * (sin x) =  x sin(x)cos^(x1)(x) (dy/dx)(dx/du)=

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)

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?

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 +

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 = xy theta = cos^1(xy) b.) cosy=x^2 cos(y) = x^2 y = Cos^1(x^2)

Maths
How do I do this Need details solution to follow up prove that cos(a)+cos(a+b)+cos(a+2b)+....+cos(a+(n1)b)={cos(a+((n1)/2)bsin(nB/2)}/½sinb for all N£N

Maths:Trigonometry
How do I do this Need details solution to follow up prove that cos(a)+cos(a+b)+cos(a+2b)+....+cos(a+(n1)b)={cos(a+((n1)/2)bsin(nB/2)}/½sinb for all N£N ???

trig
Show that 1cos2A/Cos^2*A = tan^2*A 1cos2A/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)

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 +

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

Math
Solve this equation algebraically: (1sin 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.

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

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

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

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

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(

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,

Math Help Please
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

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

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 cos4(x)*3sin(x)dx If you let u = cos(x) then du =

Calculus
Find the velocity, v(t), for an object moving along the xaxis 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

Trigonometry
I need to prove that the following is true. Thanks. csc^2(A/2)=2secA/secA1 Right Side=(2/cosA)/(1/cosA  1) = (2/cosA)/[(1cosA)/cosA] =2/cosA x (cosA)/(1cosA) =2/(1cosA) now recall cos 2X = cos^2 X  sin^2 X and we could say cos A = cos^2 A/2  sin^2

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 +

precal
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 

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)).

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 306090 triangles. If the hyp is 2, the shorter side is 1, and the longer side is sqrt3. what does

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

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)]

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)^(x1) * (sin x) =  x sin(x)cos^(x1)(x) (dy/dx)(dx/du)=

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(14575) = sin

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

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 +

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

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 +

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

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(1sin x/cos x)=1 1/cos x + sin x/cos x(cos^2 x/cos x)=1 1+sin x/cos

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

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 =

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

Calculus  MathMate Please help
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

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

Math(Please check)
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?

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

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

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

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

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 = xy theta = cos^1(xy) b.) cosy=x^2 cos(y) = x^2 y = Cos^1(x^2) your post confused me a

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?

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

Trigonometry(please Clarify)
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 = xy theta = cos^1(xy) b.) cosy=x^2 cos(y) = x^2 y = Cos^1(x^2) your post confused me a little.

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

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

Math
Prove each identity: a) 1cos^2x=tan^2xcos^2x b) cos^2x + 2sin^2x1 = 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.

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

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(2cos^2) x^2(21/x^2) = 2x^2  1 x^2  y^2 = 1 My teacher said to use

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^(n1)u sinu + (n1/n)∫sin^(n2)u du = 1/4 cos^(41)u sinu + (41/4)∫sin^(42) u du so what i did the problem: let u=3x then du=3dx =1/4*1/3 cos^3u sinu +

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)

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

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)

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 sumtoproduct formula to rewrite the expression sin6x  sin9x I don't really understand

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

Calculus
how do you solve this trig identity? i don't get it at all! cos(a+b)cos(ab)=cos^2acos^2b1

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

Calculus repost
Does anybody know how to solve this question? a) Find the arc length function for the curve measured from the point P in the direction of increasing t from P and then reparametrize the curve with respect to arc length starting from P. b) Find the point 4

Calculus
Which of the following is the best linear approximation for f(x)=cos(x) near x= π/2 ? a) y= x  π/2 b) y= x + π/2 c) y= x + π/2 + 1 d) y= x  π/2 +1

PreCal
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.

Engineering
From the following two linear homogeneous algebraic equations:(sqr= square root) (1) B*sin(kl/sqr2) = D*sin(kl) (2) (k/sqr2)*B*cos(kl/sqr2) = (k)*D*cos(kl) Form matrix of these 2 equations and solving the determinant=0 will lead to:

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

PreCalculus
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 tsin^4 t=12sin^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

trigonometry (please double check this)
Solve the following trig equations. give all the positive values of the angle between 0 degrees and 360 degrees that will satisfy each. give any approximate value to the nearest minute only. 1. sin2ƒÆ = (sqrt 3)/2 2. sin^2ƒÆ = cos^2ƒÆ + 1/2 3. sin 2x

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:

AP Calculus
Find the velocity, v(t), for an object moving along the xaxis 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

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

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

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 = 12Cos^2 Y. let y= x/2, and 2Y=x