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

4,795 questions, page 22
1. Trigonometry

Γ is the circumcircle of triangle ABC with radius 12√2. If 9cos(∠B+∠C)cos∠A=−1, what is the value of BC?

asked by Shin on May 21, 2013
2. Math

verify: sin^3 x - cos^3 x = (sinx+cosx)(1-sinxcosx)

asked by Anonymous on January 25, 2011
3. MATHS - URGENT

Write the expression in terms of sine only. 8(sin 2x − cos 2x)

asked by Shane on May 21, 2013
4. pre-cal

verify the identity... cot(-a)cos(-a)+sin(-a)=-csc(a)

asked by Anonymous on February 2, 2011
5. maths

dy/dt = -t^3y^2-ty^2 dx/dt=(sin t)/(cos t+10) dy/dx -3y/x =x^3cosx Which differential method should be used for each equation?

asked by s17 on March 2, 2017
6. Opt math URGENT

prove that : cos^3(θ)sin^2(θ)=1/16[2cos(θ)-3cos(θ)-5cos(θ)]

asked by Rabin on August 9, 2016
7. math 12

Could you please show me how to solve this question.If 2 cos A-1=0, where 0< or = A < 2pi what is A equal to?

asked by Tori on March 19, 2010
8. Pre Calculus

Verify the identity: cos x + sin x tan x = sec x.

asked by Kim on March 23, 2011
9. Math

Evaluate the identity (cos^2x-sin^2x)/(1-tan^2x)=cosx^2X

asked by Katelyn on March 30, 2011
10. trig

asked by Tor on May 9, 2011
11. trig

find sin if cos(2è)=(4)/(5) and theta terminates in quadrant 1

asked by Anonymous on May 9, 2011
12. Pre-Calc

cos^3 = (1/2 cosx)(1+cos2x) Please make the left match the right.

asked by Amy on January 24, 2018
13. Math

Rewrite in terms of an expression containing only cosines to the power 1. 4 cos^6x

asked by Sarah on March 17, 2013
14. calculus

Use the Table of Integrals to evaluate the integral (x sine(6x^2)cos(7x^2)dx)

asked by ali on February 14, 2010
15. Trig

Rewrite cos(tan^-1(v)) as an algebraic expression in v. Can someone help me with this problem? Thanks

asked by Jennifer on May 15, 2011
16. calculus

find the lim cos 2x/(5 + x) as x approaches pos. inifinity

asked by dee on February 14, 2010
17. Math

Transform to a Cartesian Equation: a. x = sin t y = cos t b. x = t^(1/3) -1 y = t^2 - t --- This is what I have for B so far: y = t(t-1) t = (x+1)^3 y = (x+1)^3[(x+1)^3-1] = (x^3 + 3x^2 + 3x + 1)[x^3+3x^2+3x] ...??? and IDK about A. Help? Thank you so

asked by Anonymous on February 11, 2010
18. math (differential equation)

show that y sub n=cos(ncos^-1(x)) satisfies the differential equation: (1-x^2)(d^2y/dx^2)-x(dy/dx)+n^2(dy/dx)=0

asked by shoosh on March 3, 2013
19. math

f(t) = \int_0^t \frac{x^2+11 x+24}{ 1+\cos^2(x)} dx At what value of t does the local max of f(t) occur? t = ?

asked by Anonymous on June 29, 2015
20. maths

how can i find a general solution of g(x)when they give me g(X) =cos (x+30)and g(X)= -2sinx

21. Math

A simplified version of the expression 2sinθ (cos θ)(cotθ) is

asked by TeeKay on October 13, 2014
22. precalculus

find the exact value: cos^-1 (square root of 2 divided by 2)

asked by john 2020 on March 8, 2010
23. math

In triangle ABC if

asked by ashley on April 18, 2011
24. math

In triangle ABC if

asked by ashely on April 18, 2011
25. Algebra 1

In triangle ABC ,if

asked by Maram on April 19, 2011
26. math

In triangle ABC ,if

asked by Maram on April 19, 2011
27. math

how do I find the sin, cos, and tan of -60 degrees without using a calculator?

asked by chris on December 14, 2008
28. maths period help

find the period cos(theta/4) step plz

asked by weryiyemi on March 18, 2017
29. trig help

verify that cos(A-B)/cosAsinB=tanA+cotB is an identity

asked by sam on April 14, 2008
30. trigonometry

How to verify this identity: 1+ tan x (over) = secant x sine x + cos x

asked by Debi on February 24, 2010
31. math

find the sum cos^2(j) + sin^2(j), if j = p/3 -do I have to use a pythagorean identity?

asked by Matt on January 24, 2016
32. pleeaasee hellpp!!

if sin A= the square root of eleven over 7, find the value of cos 2A.

33. Trigonometry

evaluate cot 2x = 5/12 with 0

asked by David on November 28, 2013
34. trig

find cos(θ)ˏsin(θ)ˏtan(θ), if cot (2θ)=5/12 with 0≤2θ≤π Answer this Que

asked by Anonymous on November 27, 2013
35. Math Analysis

Find the exact value of cos(x/2) if sin x = 3/4 and x is in quadrant II. ==> I got ã(4-ã7)/2. Is this correct?

asked by Emily on May 3, 2010
36. Maths

Solve for x: 5sin(2x) + cos(x) = -1.916 Can someone please show me the steps?

asked by Claire on October 17, 2010
37. math

verify, 1+csc - 0 ---------- = sec0 cos(-0)+cot(-0) 0 is angle.

asked by am on October 17, 2010
38. Trigonometry

Prove that (3cos^2x + 8sinx-8/cos^2x) = (3sinx-5/sinx+1)

asked by Trig on November 9, 2008
39. math !!

solve the equation for the interval 0

asked by Amy on September 6, 2008
40. math

Use logarithmic differentiation to find the derivative of the function. y = (cos 2x)x

asked by mat on April 5, 2014
41. math, trig

What is the exact value of the cos of 23pi/12? (Twenty-three pi over 12, which is = to 345 degrees.) Thank you

asked by roger on April 26, 2010
42. calculus

Prove that cos(sin inverse x) = square root ( 1-x^2)

asked by Samantha on September 29, 2010
43. calculus

Prove that cos(sin inverse x) = square root ( 1-x^2)

asked by Samantha on September 29, 2010
44. Calculus

Find the derivative. g(x)=cos(x^6) Isn't the answer -6xsin(x^6)

asked by George on September 27, 2008
45. Trig

given that sinx=3/4 and cosy=-5/13 and both x and y are in quadrant II, find the exact value of cos(x-y)

asked by Blaire on March 2, 2014
46. Math

Given cot u=2/5 and cos v=-3/5 find tan(u+v) assume 0

asked by Blaire on March 2, 2014
47. Physics, math

What is the answer to this? I don't understand how to solve it. 1.2 = 4.6 tan 50 - 4.9 (4.6^2)/(x^2 cos^2 50)

asked by Taylor on September 27, 2015
48. Calculus

Can someone help me to integrate by substitution the indefinite integral: (sinx)/ (1+cos(^2)x)?

asked by Em on July 24, 2010
49. Calculus

(sin(47))^2 + (cos(43))^2 = With the correct number of significant figures.

asked by jim on August 24, 2010
50. maths trigonometry

Expand the following using compound angle formulae Sin(m-n) Cos(p-55)

asked by amanda on January 16, 2017
51. Math

f(x) = cos(x) + 3x Find f^-1 (1) and (f^-1)' (1) f^-1 (1) = 0 (f^-1)' (1) = 1/3 These are the answers given, but I also don't understand how my teacher got these.

asked by Dave on December 5, 2016
52. Math

Simplify the expression csc@cos@tan@. What is the best way to solve this?

asked by V on September 5, 2010
53. Math

Solve this multiple-angle equation. cos x/2 = -(sqrt3)/2

asked by Anonymous on October 18, 2015
54. Calculus

Find dy / dx by implicit differentiation. 2sin(9x)cos(3y)=3 dy/dx=_____

asked by Starfallen on October 25, 2010
55. Trig

If sec A =5/4 and A is an angle in Quadrant IV, find the value of cos A. A. -4/5 B.4/5 C.-5/4 Is it choice A

asked by Kiki on April 26, 2014
56. Trignometry

Write the complex number in the form a=bi √(3)(cos π/3 + isin π/3)

asked by yes on July 2, 2013
57. Calculus

show the following linearization of the function f(x)=cos(3x)-3sin(3x) at x=2pi

asked by Jay on April 7, 2010
58. trig, math

Which of these functions has period 7? A)y= cot 7/pi x B)y= tan pi/7 x C)y= sin 7/pi x D)y= cos pi/7 x

asked by John on July 1, 2013
59. Calculus

Find the equation of the tangent line to f(x)=sec x - 2 cos x at (pi/3, 1).

asked by Anonymous on August 30, 2015
60. Calculus

prove if an identity csc (x)-cot (x)=sin (x)/1+cos(x)

asked by Anonymous on October 15, 2018
61. Trig

asked by Kay on December 31, 2010
62. Math Trigonometry

Given w=2+2i and v=−5√3+5i, vw^2 can be expressed as r*(cos(α∘)+i*sin(α∘)), where r is a real number and 0≤α≤360. What is the value of r+α?

asked by Crow on June 21, 2013
63. trig

Find all real numbers in [0, 2π) that satisfy the equation. cos 2x = √(2)/2

asked by tony on June 17, 2013
64. trig

Given that cos A = 5/13 and A and B are both acute angles, calculate the value of Sin2A and Cos2A

asked by uche on June 6, 2014
65. trig

simplify the expression. (sin^2x+cos^2x) - (csc^2x-cot^2x)

asked by trig on July 14, 2013
66. trig

simplify the expression. cos^2x+sin^2x/cot^2x-csc^2x

asked by tony on July 14, 2013
67. Algebra 2

Find the period and the amplitude of the periodic function. y=-4 cos 8x

asked by Austin on May 19, 2014
68. Math

The point (5,-2) in on the terminal side of an angle t. Find cos

asked by Brandon on November 16, 2016
69. calculus

Find the derivative r '(t) of the vector function r(t).

asked by Mike on April 20, 2010
70. Trigonometry

Solve the following equation tan (2x)+ sec (2x) = cos (x)+ sin (x) Thanks for your help

asked by Tommy on July 24, 2008
71. PreCalc

Verify the Identity. cos^4xcsc^2x = csc^2x + som^2x - 2

asked by Brit on November 1, 2017
72. calculus help

find the derivative of the function. integral cos(x) to sin(x) ((ln(8+3v))dv)

asked by Kevin on May 1, 2014
73. Trigonometry

Prove the identity. 6cos^2(x)-1 -12cos^4(x) +8cos^6(x)= cos^3(2x) Thanks for your help :)

asked by Tommy on July 18, 2008
74. Math

If x is an angle in the first quadrant and cscx = 3 find the exact value of cos 2x

asked by Nicole on April 15, 2010
75. precalc

solve in degrees 1) 2sin2 (x/4) = 1 2) 2 cos (3x) + 1 = 0 3) cot2 (x + 18°) = 1 4) (1 + tan(x + 87°)) / 2 = 7

asked by yani on October 27, 2015
76. Algebra 2

Find the exact value of cos 315 degrees. answers: 3/2, -1/2,2/2, -2/2

asked by Pam on May 19, 2014
77. Trigonometry

Verify the identity: cos x + sin x tan x = sec x.

asked by CJ on January 13, 2011
78. trig

if cos(theta) equal -3/4 find sin(2theta)

asked by Anonymous on September 1, 2011
79. pre cal

show that 6+6sin X is equivakent to --------- - 7 cos x 6cos x ------------ -7(1- sin x)

asked by colleen on February 16, 2009
80. Math

use the unit circle to prove that tan(x/2) = (sin(x))/(1+cos(x))

asked by Zack on December 12, 2012
81. math

how do I do this? I think I have to simplify it? (sin^2ө + cos^3ө/sinө + cosө)+ sinөcosө

asked by maggie on February 12, 2009
82. Math

y = 4 cos (3/4) θ a. amplitude = 4 b. number of cycles = ? c. period = (8pi/3)

asked by Anonymous on May 25, 2018
83. calculus - identities

prove this identity: sec(y) - cos(y)= tan(y)sin(y) THANK YOU!!

asked by Amber on October 16, 2009
84. Calculus

maximum and minimum of y = cos(x) + sin (x)on the interval [0,2pi]

asked by Mark on October 25, 2009
85. amth

Solve the multiple-angle equation. cos x/2 = - squareroot 3/2

asked by elise on July 11, 2016
86. calculus

find the derivative of y=cos pix/sinpix+cospix

asked by vicki on October 9, 2011
87. Pre Calculus

Find the exact value ofcos (u+v) given that sin u= 7/25 and cos v=−12/13. (Both u and v are in Quadrant II.)

asked by Jessica Maths on July 11, 2016
88. trig, precalc, math, algebra, trigonometry

asked by Veronica on May 5, 2016
89. calculus-derivatives

y=cos^3(12theta) find derivative using chain rule

asked by hailey on September 27, 2011
90. maths

Express sin 2x cos 4x as a sum of trigonometric functions

asked by tom on December 24, 2012
91. maths

Express sin 2x cos 4x as a sum of trigonometric functions.

asked by laura on December 23, 2012
92. Calculus

Which of the following functions does not have a derivative of zero? A. y=-1/100 B. y=4(pi)^2-9 C. y=sin^2x+cos^2x D. y=cscxtanxcosx E. All do

asked by Anonymous on December 1, 2014
93. Calc

find F''(pi/3) f(x)= 4cos(x/2) i got -cos(pi/6) but i don't think that's the correct answer... Thanks!

asked by Lilly on September 11, 2011
94. TRIG

THE SIN COS SEC TAN COT CSC 5X+Y=0

asked by NAUDIA on September 20, 2011
95. trig

Use a half-angle formula to find the exact value of cos 5ð/12

asked by Steve on December 16, 2009
96. Trigonometry

Prove that sin(n+1)Asin(n+2)A + cos(n+1)Acos(n+2)A = cosA

asked by Kewal on December 30, 2011
97. Trigonometry

Prove that sin(n+1)Asin(n-1)A + cos(n+1)Acos(n-1)A = cos2A

asked by Kewal on December 30, 2011
98. calculus

Find any critical numbers of the function h(x)=sin^2(x)+cos(x) 0 < x < 2π

asked by Anonymous on October 30, 2012
99. trig

cos t=.7, tan t

asked by Marni on November 27, 2011
100. Trig

Find all real numbers that satisfy the equation. 2 cos x + 1 = 0

asked by Anonymous on November 1, 2011