trig proofs

• May 23rd 2010, 07:06 PM
runner940
trig proofs
I am having difficulty getting past the first step of solving this problem, can someone help me or check this for me? Thank you (Nod)

Original Problem: sin(x)^2 - sin(x)^4 = cos(x)^2 - cos(x)^4
• May 23rd 2010, 07:08 PM
Prove It
Quote:

Originally Posted by runner940
I am having difficulty getting past the first step of solving this problem, can someone help me or check this for me? Thank you (Nod)

Original Problem: sin(x)^2 - sin(x)^4 = cos(x)^2 - cos(x)^4

$\sin^2{x} - \sin^4{x} = \sin^2{x}(1 - \sin^2{x})$

$= \sin^2{x}\cos^2{x}$

$= (1 - \cos^2{x})\cos^2{x}$

$= \cos^2{x} - \cos^4{x}$.