1. ## Identity transformation problem

Hi,

I'm having trouble with the pictured problem.

I understand that 1=sec2-tan2 and 1=cos2/cos2, but having issues with working through 1=(1-(?))/cos2.

Any help would be greatly appreciated.

Thanks!

2. ## Re: Identity transformation problem

$\sec^2(\theta)-\tan^2(\theta) = \dfrac{1 - \sin^2(\theta)}{\cos^2(\theta)}=\dfrac{\cos^2( \theta)}{\cos^2( \theta)}=1$