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

4,795 questions, page 36
1. ## Dynamic n vibration, physics

A system is represented by the equation: 2x”+128x = f(t) Obtain the free response of the system in the form a) x = A sin wn (t ) + B cos wn (t) b) x= A sin wn (t) + ϕ The initial conditions are x(0) = 0.05m and x’ = 0.3m/s.

2. ## Math for Reiny

your derivative is correct. now just plug in x = π/2 to get the slope remember that tan(π/2) is undefined, BUT cot (π/2) = cos(π/2) / sin(π/2) = 0/1 = 0 so slope = -csc^2 (π/2) = 2 I calculated and got -1 as the slope. Can you please explain how you

asked by Dave on October 12, 2016
3. ## Math for Reiny

your derivative is correct. now just plug in x = π/2 to get the slope remember that tan(π/2) is undefined, BUT cot (π/2) = cos(π/2) / sin(π/2) = 0/1 = 0 so slope = -csc^2 (π/2) = 2 I calculated and got -1 as the slope. Can you please explain how you

asked by Dave on October 12, 2016

given that sinx, tanx, and sin2x form geometric sequence, show cos^3x=1/2 can someone explain this to me, i have no idea how to solve it. i really done understand how to turn it into a geometric sequence

asked by AA on November 5, 2016
5. ## Calculus

Consider the following. cos(x) + sqrt(y)= 1 (a) Find y' by implicit differentiation. y' = Correct: Your answer is correct. (b) Solve the equation explicitly for y and differentiate to get y' in terms of x. y' = ? (c) Check that your solutions to parts (a)

asked by Anonymous on May 11, 2018
6. ## Physics

Keisha throws a baseball with an initial velocity of 30 m/s at 30.0° above the horizontal. If air resistance is negligible, how long does it take for the baseball to reach the maximum height of its trajectory? Assume that the acceleration due to gravity

asked by Jared on September 23, 2016
7. ## Math

The hypotenuse of,c of right triangle ABC is 7.0 m long. A trigonometric ratio for angle A is given for four different triangles. Which one of these triangles has the greatest area? Justify your decision. a)sec A=1.7105 b)cos A=0.7512 c) csc A=2.2703 d)sin

asked by Emily on November 26, 2010
8. ## precalculus

Can you check my work? sketch the curve represented by the parametric equations. Then eliminate and write the corresponding rectangular equation whose graph represents the curve. x=2+3cosθ y=2sinθ answer: cosθ=x/5 sinθ=y/2 cos^2θ + sin^2θ=1

asked by Anonymous on December 14, 2016
9. ## maths

Xsin(theta)-Ysin(theta)=sqrtX^2+Y^2 and cos^2(theta)/a^2+sin^2(theta)/b^2=1/X^2+Y^2 then find correct relation

asked by aakash on April 24, 2014
10. ## Trig Question

Given that tan x= -3/4 and x is in the second quadrant. Find sin 2x, cos 2x, and tan 2x (Exact, no decimals). Please show step-by-step, thank you!

asked by Anonymous on April 26, 2012
11. ## math

Sin(2x)=2sin(x)cos(x) find the exact value in radians with 2sin^2(x)+sin^2(x)=0, i really do not get this question or even how to do this ive been trying to figure it out but cant

asked by john on November 16, 2012
12. ## math

Sin(2x)=2sin(x)cos(x) find the exact value in radians with 2sin^2(x)+sin^2(x)=0, i really do not get this question or even how to do this ive been trying to figure it out but cant

asked by john on November 16, 2012
13. ## Math

Evaluate the integral of (sin 2x)/(1+cos^2 x) 1. u=cosx and du=-sinx *dx 2. evaluate the integral of -1/(1+u^2)*du 3. result is -ln(1+u^2)+C Where did the sin2x dissapear too???

asked by Dave on September 13, 2017
14. ## Pre-Calculus

I really need help on this question Simplify the expression by using a Double-Angle formula or a Half-Angle Formula cos^2 0/2-sin^2 0/2

asked by Andrea on November 12, 2014
15. ## Trigonometry

Cos D= -3/4. if the sine of the angle is positive, find the sine of the angle and determine the quadrant. Can anyone tell me the steps. I need to learn this.

asked by Laly on February 18, 2010
16. ## Algebra

Verify the identity. Justify each step. tan (thetA) + cot (thetA) = 1 / sin (thetA) cos (thetA)

asked by Chris on May 7, 2019
17. ## Math

Are these correct? 5. is sin θ = -7/13 and cos θ = 12/13, find tan θ and cot θ using Quotient Identities. answers: tan (θ) = -(7/12) cot (θ) = -(12/7)

asked by Anonymous on March 25, 2019
18. ## Trigonometry

How am I suppose to transform the left side of the equation into the right side using trig identities? ): 1) sin^2θ - cos^2θ = 2 sin^2θ - 1

asked by Sira on January 10, 2013
19. ## Pre-Cal

Suppose that cosx= -3/5 and x is in the third quadrant, and that siny= 2/9 and y is in the second quadrant. Find the exact values 1). tan(y/2) 2). cos(x+y) 3). tan(x+y)

asked by Help on July 12, 2016
20. ## physics

The position of a mass oscillating on a spring is given by x = (5.6 cm) cos [2πt / (2.03 s)]. (a) What is the period of this motion? (b) What is the first time the mass is at the position x = 0?

asked by aok on November 18, 2010
21. ## Trig

find the exact value of the expression using the provided information. Find Tan (S+T) given that cos s=1/3 with s in quad I and sin T= -1/2 with T in quad IV

asked by Paige on February 18, 2011
22. ## Trigonometrt

Express in functions of theta: a. sin ( 810- theta) b. cot ( theta - 360) c cos (-180- theta)

asked by Fern Angel on April 9, 2016
23. ## trigonometry

1)Solve and write in standard form: 4x^2-4x+21=0 2)Find the standard form of the complex number. 8(cos pi/2 + i sin pi/2) Thanks everyone!

asked by mikey on December 3, 2012
24. ## Maths

Find a if a is between 0 degrees and 180 degrees, and: a. Sin a = cos a b. sin^2 = 3/4 c. tan^2 = 1/3 I have no clue on where to start any help would be much appreciated.

asked by Rick on September 28, 2017
25. ## Calculus

Show that y= x + sinx-pi satisfies the initial value problem dy/dx=1 + cos x, y(pi)= 0 i don't understand how to do this problem. i don't know where to begin.

asked by Dan on November 18, 2008
26. ## Calculus

For 0 < x < PI/2, if y = sin(x)^x, then dy/dx is.. I understand that you can take the natural logarithm of both sides and then take the derivative but why can't I simply take the derivative of it and get.. dy/dx = x(cos(x))(sin(x))^(x-1). Thanks in advance

asked by Anonymous on March 30, 2008
27. ## trig

Verify the trigonometric identity. Please show all steps. tanx-cotx/tanx+cotx=sin^2x-cos^2x

asked by garrett on March 4, 2012
28. ## Pre Calculus

Find the magnitude and direction angle for the vector v=3 cos 123 degrees i + 3 sin 123 degrees j.

29. ## Trigonometry Help

asked by Anonymous on February 21, 2012
30. ## Trig

Show that the following statement is an identity by transforming the left side into the right side. sinθ(cscθ − sinθ)= cos^2 θ

asked by Kim on January 31, 2018
31. ## trigonometry

given tanθ= -2√10/3 and π/2

asked by Yulieth on November 20, 2011
32. ## Physics

The position of a mass oscillating on a spring is given by x=(4.7 cm)cos [2pi t/(0.52 s)]. What is the period of this motion? What is the first time the mass is at the position x=0?

asked by Cooper on November 17, 2011
33. ## MATH

prove tan (theta/2)= (sin(theta))/(1+cos(theta))for theta in quadrant 1 by providing the calculation along with the reason. I appreciate the help.

asked by LIZZIE on January 29, 2014
34. ## Trig

find the exact value of the expression using the provided information. Find Tan (S+T) given that cos s=1/3 with s in quad I and sin T= -1/2 with T in quad IV

asked by Patti on February 19, 2011
35. ## pre calculus

ea + bi = ea(cos b + i sin b) This formula gives rise to the equation eπi + 1 = 0. . Show how Euler’s formula can be used to derive this equation.

asked by Anonymous on November 26, 2016
36. ## Trig

Give: a=alpha B=beta csc a= 2 pi/2

asked by Sierra on November 7, 2012
37. ## math

Find the integral given below. integral cos^2(7x+1)dx

asked by Carl on September 12, 2018
38. ## Calculus

Does f(x)= 1 + cos(x), have an inverse or not, if so, what is the inverse? please explain.

asked by Carrie on February 15, 2011
39. ## math

how to simplify: {cos(x)/sin(x)} / (sin^2 (x))

asked by jasmine on March 26, 2009
40. ## ãåîìåòðèÿ

Cos 600º + sin 600º -?

asked by Àëåêñàíäð on March 17, 2014
41. ## Math

cot (theta)=-9/8, cos (theta)

asked by David on June 14, 2010
42. ## Math

Show that sin (α-30°)+cos (α+30°) = (√3 - √1)/√2 × sin (α+45°)

asked by NR on May 22, 2017
43. ## Maths

sin(x)+cos(x)=2/3 find the value of sin(x)

asked by Shubham on May 22, 2008
44. ## pre cal

simplify sin (8x) using only sin(x) and cos (x)

asked by Terri on June 29, 2012
45. ## trig

inverse tan x = inverse cos 4/5

asked by makaela on May 16, 2012
46. ## precalculus

Let z1=2(cos 2pi/3+isin 2pi/3) what are z1^(1/3)?

asked by jk on March 31, 2015
47. ## precalculus

Let z1=2(cos 2pi/3+isin 2pi/3) what are z1^(1/3)?

asked by jk on March 31, 2015
48. ## Trigonometry

If sin(x) = 4cos(x), then what is (sin(x))*(cos (x))?

asked by Katie on April 4, 2016
49. ## precal

sinx(ccscx-sinx=cos^x

asked by Anonymous on March 23, 2012
50. ## maths

if sin A = 3/5 and cos A is less than 0,determine the value of sin (-A)

asked by sbonelo on March 7, 2014
51. ## math

Please help. given the units for four of the six variables, what must be the units of z and y? a=m t=s/K h=N^4 x=m z^a=xh cos(yt)

asked by lexy on October 23, 2016

53. ## Trig

I need to the steps to get (1-sinx)(1+sinx)=cos^2 x

asked by Jaime on October 28, 2014
54. ## trigonometry

If cos x = 4/5, 0° x 90°, find the value of (1 + tan x)/(1 - tan x)

asked by Lucky on April 8, 2017
55. ## Math

(cos^4x -sin ^4 x)/(sin^2x)=cot^2x -1

asked by Anonymous on November 10, 2014
56. ## calculus2

How do I evaluate this integral? integral from 0 to 24 of the √(1+[(π/3)*cos((πx/3)]^2)

asked by A on July 21, 2018
57. ## Cosine question

cos theta= .5 2cos theta= .5 how do you do this?

asked by Diana on January 9, 2012
58. ## Math

Let ∠X and ∠Y be complementary. If sin(X) = 3/5 and cos(X) = 4/5 then what is the value of sin(Y)? A)3/5 B) 4/5 C) 5/4 D) 5/3 Is it A?

asked by Yolanda on August 8, 2015
59. ## math

cos^2 theta - sin^2 theta = 1

asked by Amirul Thaqif on February 2, 2013
60. ## Trigonometry

cos2Acos2B + sin²(A-B) - sin²(A+B) = cos(2A+2B)

asked by Kewal on January 12, 2012
61. ## math

asked by math genius on December 21, 2011
62. ## trig

cos^(2) 20 degrees + sin^(2) 20 degrees +pi/2

asked by Anonymous on February 17, 2013
63. ## maths

how does 2sin(a/2)cos(((m+1)/2)a) = sin(((m+2)/2)a) - sin ((ma)/2)?

asked by nn on June 30, 2011
64. ## Trigonometry

cos 17pi/6 + tan 17pi/6

asked by dan on January 23, 2013
65. ## Math

asked by Unknown on May 27, 2018
66. ## trig

prove: cos*2x=csc*2x-2/csc*2x

asked by Sarah Fuller on March 9, 2010
67. ## Pre-calc

If Theta= -7pi/6; then cos(Theta) is...

asked by Jane on October 25, 2014
68. ## Math (Trig)

I have a unit circle graph like the one at the top of a website (do a google search for 'unit circle trig functions' and click the second link, since I can't post links). I need to label the sine, cosine, tangent, secant, cosecant, and cotangent. I found

asked by Chris on March 18, 2007
69. ## Physics..=> drwls - I need your help

I need help seeing if my thoughts are correct and how to do some things. Block 1 of mass 0.200 kg is sliding to the right over a frictionless elevated surface at a speed of 8.00 m / s. The block undergoes an elastic collision with stationary block 2, which

asked by ~christina~ on February 26, 2008
70. ## physics (simple harmonic motion)

If the phase angle for a block-spring system in SHM is π/5 rad and the block's position is given x = xm cos(ωt + ϕ), what is the ratio of the kinetic energy to the potential energy at time t = 0?

asked by rock on February 4, 2011
71. ## Cal

If the equation of motion of a particle is given by s = A cos(ωt + δ), the particle is said to undergo simple harmonic motion. s'(t) = -Aω sin(ωt + δ) When is the velocity 0? (Use n as the arbitrary integer.) t= _____________ I thought it was 0, but

asked by Nykie on November 29, 2011
72. ## physics

The function y(x, t) = (25.0 cm) cos(ðx - 15ðt), with x in meters and t in seconds, describes a wave on a taut string. What is the transverse speed for a point on the string at an instant when that point has the displacement y = +22.0 cm?

asked by tom on May 13, 2011
73. ## CALCULUS

Use a graphing calculator to solve the equation -3 cos t = 1 in the interval from 0 ≤ θ ≤ 2π Round to the nearest hundredth. so i put it in a graphing calculator online and now i understand what i am supposed to write or do can someone please help

asked by hello :) on February 4, 2019
74. ## Diff eqn- IVP

The differential equation that governs the forced oscillation is shown below: 0.2 d²y/dt² + 1.2 dy/dt +2y = r(t) where r(t) is the external force. Given that r(t) = 5 cos 4t with y(0) = 0 . find the equation of motion of the forced oscillations

asked by shasha on March 14, 2011
75. ## calculus

need help simplifying some trig identities such as: (csc t) (sin t) cos t = 0.75 and tan t = 0.88, find sec t and cot t; (cot2t) (sin2t) + sin2 t; csc2t - cot2t/sin2t

asked by angelia on March 25, 2012
76. ## Calculus

The height (in feet) at time t (in seconds) of a small weight oscillating at the end of a spring is given below. h(t) = 0.2 cos(2t) (a) Calculate the weight's average velocity over the time intervals [1, 2] and [5, 7].

asked by Lindy on January 26, 2013
77. ## Calculus I

We're reviewing limits from the previous chapter, but I'm still having some difficulty with some problems: lim tan(pi(x/4)) as x-> -7 lim (x^2 - x^3(cos(1/x))/3x^2 as x-> 0 I know the answer to the first problem is 1 and to the second problem it's 1/3 but

asked by Emily on January 30, 2012
78. ## Math

An equation of the tangent line to the curve y=f(x)=x(4cosx−6sinx) at the point (3f(3)) is y =? Note: Please follow these instructions carefully: (a) Express f(3) and f(3) in terms of . Simplify those expressions by evaluating the exact values of sin(3)

asked by Sam on November 5, 2013
79. ## physics

A horizontal spring mass system is set up to keep time so that it goes from one side to the other in 6 seconds. The mass used in this system is 0.69 kg. The distance from one side to the other is 2.4 m. What spring constant should be used if it is to

asked by sunny on December 31, 2012
80. ## Math

The displacement from equilibrium of an oscillating weight suspended by a spring is given by y(t) = 2 cos 6t, where y is the displacement in centimeters and t is the time in seconds. Find the displacement when t = 1.45, and round your answer to four

asked by Anonymous on September 10, 2015
81. ## Trigonometry

I am having problems with proving identities that has a number and an exponent with it. Like: *2cosxcsc2x = cscx *sin^2 2x = 4sin^2 x cos^2 x *cot2(theta)=csc(theta)-2sin(theta)/2cos(theta)

asked by Jam on October 29, 2014
82. ## Math Calculus I

let f(x)= 6sin(x)/(2sin(x)+6cos(x)) The equation of the tangent line to y= f(x) at a= pi/6 can be written in tthe form y=mx+b where m=? b=? I found the f': (9*(cos^2(x)+sin^2(x)))/(3cos(x)+sin(x))^2 but i don't know how to fill it into the form. Can anyone

asked by Anonymous on May 30, 2016
83. ## calculus

Find a number x0 between 0 and pi such that the tangent line to the curve y = sin x at x = x0 is parallel to the line y = -x=2. I get that for both lines to be parallel to each other their slopes need to be the same. I found -1/2 = cos(x) but I get stuck

asked by asdf on December 1, 2012
84. ## Calculus

h(x)= x + cos(ax), where a is a positive constant such that 0 < a < 4. For what values of a will h(x) have a relative maximum at x=1? So I found the derivative and got h'(x) = 1- asin(ax). Then I plugged in 1 for x and set the derivative equal to zero, so

asked by ashley on May 1, 2015
85. ## trigonometry

tan 30degrees = sin 60degrees /1+cos 60degrees I pluged in the numebrs and i got this . ã3/3= ã3/2 / 1+1/2 now i don't know how to work the problem to get the answer which is supposed to be ã3/3=ã3/3 i want an explaintion cuz i want to know how

asked by Cas on December 29, 2010
86. ## rate of change

For a person at rest, the function p(t) = -20 cos(300˚t) + 100 models blood pressure, in millimeters of mercury ( mm Hg), at time t seconds. What is the rate of change in blood pressure at 3 s?

asked by sara on June 9, 2012
87. ## trig

I asked below but I guess it was not understood what I was asking. I'll try again. Could someone show me how, (- sin (x/2) /( 2 sin (x/2) + cos (x/2)) is an alternate representation for, 1 / ( 4 tan (x/2) + 2 ) TIA Carol I know the half-angle formulas are

asked by Carol on January 3, 2011
88. ## AP Calc B/C

Find the arc length of one arch of the sine curve. I started it by doing y=sinx, y'=cosx arc length= integral of sqrt(1+cos^2x)dx from pi/2 to 3pi/2 but I don't know how to integrate that! Thank you!

asked by Anon on September 13, 2014
89. ## trigonomentry...Very hard

express root(9+x^2) as a trigonomentric function of tita without using radicals by letting x=3tantita.assume that 0

asked by dam on May 2, 2016
90. ## precal

Solve the given equation. (Enter your answers as a comma-separated list. Let k be any integer. Round terms to three decimal places where appropriate. If there is no solution, enter NO SOLUTION.) 2 cos2 θ − cos θ − 1 = 0

asked by stellar on October 22, 2011

I have to find the width of a river which is represented by a right trianle. The opposite side is labeled w and the adjacent side is 1oo ft. Theta is 54 degrees. Would my equation be opp = adjacent/cos(54)?

asked by Hannah on March 23, 2010
92. ## Math

A point is sliding along a curve y^2 = 1 + cos^3(2x) at whatever speed (even depending on time). Compute the ratio of the rates of change of the vertical and horizontal coordinate with respect to time when the point is at (x, y).

asked by Bruce on November 12, 2010
93. ## Maths, dynamics

a box slides under gravity down a flat slope 3 m long. Coefficient of sliding friction is 0.2. Show that the speed of the box at the bottom of the slope is given by sqrt(6g(sin - 0.2 cos) Thanks!

asked by Anon on April 6, 2017
94. ## Calculus

h(x)= x + cos(ax), where a is a positive constant such that 0 < a < 4. For what values of a will h(x) have a relative maximum at x=1? So I found the derivative and got h'(x) = 1- asin(ax). Then I plugged in 1 for x and set the derivative equal to zero, so

asked by ashley on May 1, 2015
95. ## physics

The equation of motion of a simple harmonic oscillator is given by x(t) = (9.0 cm)cos(12πt) − (5.4 cm)sin(12πt), where t is in seconds. (a) Find the amplitude. Determine the period. (c) Determine the initial phase.

asked by Anonymous on April 29, 2018
96. ## Trigonometry

Solve the following trig equations. Give all positive values of the angle between 0 degrees and 360 degrees that will satisfy each. Give any approximate value to the nearest minute only. 3 sin è - 4 cos è = 2 Can you please help me with this one.

asked by anon on March 3, 2011
97. ## Pre-Calculus

cos^2(x) + sin(x) = 1 - Find all solutions in the interval [0, 2pi) I got pi/2 but the answer says {0, pi/2, pi} Where does 0 and pi come from for solutions? When simplifying I just get sin(x)=1

asked by George on January 15, 2010
98. ## trig

Given csc theta= 4, cot theta < 0 Find the exact values of cos theta and tan theta

asked by J on February 11, 2014
99. ## Trigonometry

Evaluate please: a.) arcsin(sin 13pi/16) b.) arccos(cos[-pi/18]) c.) arcsin(sin pi/18 d.) arcsec(-√2) e.) arctan(-√3/3)

asked by Liv on November 26, 2016
100. ## Physics

The position of a mass oscillating on a spring is given by x = (7.0 cm) cos [2πt/(0.71 s)]. (a) What is the frequency of this motion? (b) When is the mass first at the position x = -7.0 cm?