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

4,795 questions, page 36-
## 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.

*asked by Chad on October 11, 2017* -
## 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* -
## 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* -
## Advance function

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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## Algebra

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

*asked by Chris on May 7, 2019* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## trig

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

*asked by garrett on March 4, 2012* -
## Pre Calculus

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

*asked by ADOG on May 17, 2018* -
## Trigonometry Help

Simplify: sin(x-y)cosy+cos(x-y)siny = (sinxcosy-cosxsiny)cosy+(cosxcosy+sinxsiny)siny = ??? What do I do next??? Please Help and Thank You

*asked by Anonymous on February 21, 2012* -
## 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* -
## trigonometry

given tanθ= -2√10/3 and π/2

*asked by Yulieth on November 20, 2011* -
## 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* -
## 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* -
## 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* -
## 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* -
## Trig

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

*asked by Sierra on November 7, 2012* -
## math

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

*asked by Carl on September 12, 2018* -
## 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* -
## math

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

*asked by jasmine on March 26, 2009* -
## ãåîìåòðèÿ

Cos 600º + sin 600º -?

*asked by Àëåêñàíäð on March 17, 2014* -
## Math

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

*asked by David on June 14, 2010* -
## Math

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

*asked by NR on May 22, 2017* -
## Maths

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

*asked by Shubham on May 22, 2008* -
## pre cal

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

*asked by Terri on June 29, 2012* -
## trig

inverse tan x = inverse cos 4/5

*asked by makaela on May 16, 2012* -
## precalculus

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

*asked by jk on March 31, 2015* -
## precalculus

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

*asked by jk on March 31, 2015* -
## Trigonometry

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

*asked by Katie on April 4, 2016* -
## precal

sinx(ccscx-sinx=cos^x

*asked by Anonymous on March 23, 2012* -
## 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* -
## 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* -
## Math-Derivitives

if f(x)=x^3+5x, then f'(2)= if f(x)=cos(2x), then f'(pi/4) derivatives and anti derivatives please help

*asked by AdrianV on March 23, 2010* -
## Trig

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

*asked by Jaime on October 28, 2014* -
## 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* -
## Math

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

*asked by Anonymous on November 10, 2014* -
## 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* -
## Cosine question

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

*asked by Diana on January 9, 2012* -
## 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* -
## math

cos^2 theta - sin^2 theta = 1

*asked by Amirul Thaqif on February 2, 2013* -
## Trigonometry

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

*asked by Kewal on January 12, 2012* -
## math

sin(((cos^-1)(3/5))-((sin^-1)(5/13))) help and explain please

*asked by math genius on December 21, 2011* -
## trig

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

*asked by Anonymous on February 17, 2013* -
## 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* -
## Trigonometry

cos 17pi/6 + tan 17pi/6

*asked by dan on January 23, 2013* -
## Math

Evaluate cos^2(pi/12). a)1/4 b)(2+sqrt3)/4** c)3/2 d)(2-sqrt3)/4 Please help :(

*asked by Unknown on May 27, 2018* -
## trig

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

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

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

*asked by Jane on October 25, 2014* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## Pre-Cal(please check)

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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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?

*asked by Yadan Valeton on March 22, 2015*