Posted by sandeep on Friday, August 17, 2012 at 10:16am.
dropping 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 - find the solution of the equation in [0,2pi) cos^2x-sinxcosx=0
equations trig - 8sin^2x+sinxcosx+cos^2x=4
Math - Prove each identity: a) 1-cos^2x=tan^2xcos^2x b) cos^2x + 2sin^2x-1 = sin...
Math - Solving for Trig Equations - Solve the following equation for 0 less than...
precalc - find the solution of the equation in [0,2pi) cos^2x-sinxcosx=0
equations trig - 1) ctgx+cosx=1+ctgx*cosx 2) sin^4x+cos^4x=1/2 3) (sinx-cosx)^2=...
math - I have to find an exact solutions on the interval [0,pi) for both of ...
For Further Reading
