Posted by Blaire on .
Prove: [(tan^2theta+1)(cos^2theta1)]=1sec^2theta

Math 
Damon,
tan^2 = sin^2/cos^2 = s^2/c^2
(s^2/c^2+1)(c^21) = s^2 s^2/c^2 +c^2 1
but s^2 + c^2 = 1
so we have
s^2/c^2
= (1  c^2)/c^2
=  1/c^2 + 1
= 1  sec^2