How do you verify the identity cos(pi/2-x)/sin(pi/2-x)=tanxcos(π2x)sin(π2x)=tanx?

1 Answer
Feb 6, 2017

Since

cos(pi/2-alpha)=sinalphacos(π2α)=sinα

and

sin(pi/2-alpha)=cosalphasin(π2α)=cosα,

you get:

cos(pi/2-x)/sin(pi/2-x)=sinx/cosx=tanxcos(π2x)sin(π2x)=sinxcosx=tanx