Thread: Deriving an Identity from another

1. Deriving an Identity from another

I have been trying to work out a problem from my homework set and cannot get it. I have to use the identity

sin^2(x) + cos^2(x) = 1

to derive the identity

tan^2(x) + 1 = sec^2(x)

I would appreciate it if someone could just give me a hint on how to solve this problem. I have tried this numerous ways but cannot get it.

Thanks

2. Divide both sides by $\cos^2 x$. See what you get

3. Thanks! I tried everything else except that I cannot believe I missed that