Question

. Verify the Pythagorean Identity.

Answer 1

convert  to sines and cosines:-
 1 + cot^2 x
=  1 + cos^2 x / sin^2x

=  sin^2 x + cos^2 x
    ---------------------
              sin^2 x

but sin^2 x + cos^2 x = 1

so this =  1 / sin^2x  which is the same as csc^2 x