For what values of x does sqrt((1-sinx)/(1+sinx))=secx-tanx hold?

1 Answer
Apr 16, 2017

Identity holds for all values of x, irrespective of quadrant.

Explanation:

sqrt((1-sinx)/(1+sinx))

= sqrt(((1-sinx)^2)/((1+sinx)(1-sinx))

= sqrt((1-sinx)^2/(1-sin^2x))

= sqrt((1-sinx)^2/cos^2x)

= (1-sinx)/cosx

= 1/cosx-sinx/cosx

= secx-tanx

Above is an identity and hence it holds for all values of x i.e. for any quadrant.