Question #24c10

1 Answer
Feb 9, 2017

Explained below

Explanation:

In the numerator on the left side add and subtract 1 as,

#1+tan^2 theta +cos^2 theta -1#

or, #1+tan^2 theta -( 1-cos^2 theta)#

or, #sec^2 theta - sin^2 theta#

or, # 1/(cos^2 theta) - sin^2 theta#. Now factorise it,

#(1/cos theta - sin theta)(1/cos theta + sin theta)#

The factor #(1/ cos theta + sin theta)# would get cancelled out with the denominator, leaving with the factor # 1/cos theta - sin theta#= RHS