using the fundamental identities. Man, this stuff is easy yet for some reason my head doesn't understand it at all..

So I have to convert sec, into sin which I thought was simple but Imustbe over thinking once again.

$\displaystyle secx, sinx$

Process:

$\displaystyle 1 + tan^2 = sec^2 $ (One of the fundamental identities.)

$\displaystyle sec^2 = 1 + tan^2 $

$\displaystyle sec^2 = 1 + sin^2 / cos^2$ (Changing from tangent to sin/cos)

Now here I get a little lost cause I dunno what to do with that cos. I tried doing something like..

$\displaystyle sec^2 = cos^2 + sin^2 / cos^2 $ (Multiplied 1 by the common denominator)

Dunno where exactly I went wrong or even if I did it correctly in the first place. Meh, any help on this easy problem would put my mind to ease and help me understand how to do the rest. I just want to learn how to do it correctly ><.

EDIT:

I forgot to add that the answer is secx = 1 / √(1 - sin^2). Also, is there a way to change from cos to sin? o-o