Question

Does anyone can help me to prove this too?? Thank you before ....

Answer 1

`(1)/( cos^(2) \alpha ) + (1)/( sin^(2) \alpha ) = ( sin^(2) \alpha + cos^(2) \alpha )/( sin^(2) \alpha * cos^(2) \alpha ) = (1)/(sin^(2) \alpha * cos^(2) \alpha)`