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
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
Hello, gumby456m!
Verify: .$\displaystyle \cos^4\!x- \sin^4\!x \:=\:\cos^2\!x-\sin^2\!x$
$\displaystyle \text{Factor the left side: }\;\left(\cos^2\!x-\sin^2\!x\right)\underbrace{\left(\cos^2\!x + \sin^2\!x\right)}_{\text{This is 1}} \;=\;\cos^2\!x-\sin^2\!x$