Question

cos²β(1+tan²β)=1. Show this is an identity. I have so much trouble with these....

Answer 1

It follows from
\[1+\tan^2\beta = \sec^2\beta\]

(which in turn follows from dividing the identity
\[\sin^2\beta + \cos^2\beta = 1 \text{ by } \cos^2\beta \]

Answer 2

I still don't see it. what would i do next?

Answer 3

Wait, it's easier. Just multiply out the equation you have to start and it follows immediately.

Answer 4

tan^2 = sin^2/cos^2 => tan^2 x cos^2 = sin^2

Answer 5

I'm still confused!

Answer 6

Oh dear :(