Wednesday

July 30, 2014

July 30, 2014

Posted by **sandeep** on Friday, August 17, 2012 at 10:16am.

- math -
**Steve**, Friday, August 17, 2012 at 2:54pmdropping the x's for brevity,

2cos^2 - 1 = 2sin cos

4cos^4 - 4cos^2 + 1 = 4sin^2 cos^2

4cos^4 - 4cos^2 + 1 = 4(1-cos^2) cos^2

4cos^4 - 4cos^2 + 1 = 4cos^2 - 4cos^4

8cos^4 - 8cos^2 + 1 = 0

cos^2 = 1/4 (2 ± √2)

x = kπ/2 ± π/8 for integer k

**Related Questions**

Trigonometry. - ( tanx/1-cotx )+ (cotx/1-tanx)= (1+secxcscx) Good one! ...

TRIG! - Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6...

calculus - Which of the following are antiderivatives of f(x)=sinxcosx? I f(x)=(...

math - I have to find an exact solutions on the interval [0,pi) for both of ...

math - find the solution of the equation in [0,2pi) cos^2x-sinxcosx=0

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

Math - How do factor a binomial with cubed roots? cos^3+sin^3/cosx+sinx = 1-...

equations trig - 1) ctgx+cosx=1+ctgx*cosx 2) sin^4x+cos^4x=1/2 3) (sinx-cosx)^2=...

calculus - How is the integral of cos(2x) = sinxcosx?

trigonometryy - sin^4x-cos^4x=7/2(sinxcosx)