# Math Help - Verify by transforming one side into the other

1. ## Verify by transforming one side into the other

Verify by transforming one side into the other:

cos^4 x- sin^4 x =cos^2 x-sin^2 x

ive tried transforming the left side to the right side

(cos^2 x)(cos^2 x)-(sin^2 x)(sin^2 x)

but can't figure out how to proceed

thanks for any help

2. Hello, gumby456m!

Verify: . $\cos^4\!x- \sin^4\!x \:=\:\cos^2\!x-\sin^2\!x$

$\text{Factor the left side: }\;\left(\cos^2\!x-\sin^2\!x\right)\underbrace{\left(\cos^2\!x + \sin^2\!x\right)}_{\text{This is 1}} \;=\;\cos^2\!x-\sin^2\!x$