How do you verify the identity (1+sintheta)/costheta+costheta/(1+sintheta)=2sectheta1+sinθcosθ+cosθ1+sinθ=2secθ?

1 Answer
Feb 6, 2017

see below

Explanation:

Left Hand Side:

(1+sin theta)/cos theta + cos theta/(1+sin theta)=((1+sin theta)(1+sin theta)+cos theta cos theta)/(cos theta(1+sin theta))1+sinθcosθ+cosθ1+sinθ=(1+sinθ)(1+sinθ)+cosθcosθcosθ(1+sinθ)

=(1+2sin theta + sin^2 theta + cos ^2 theta)/(cos theta(1+sin theta))=1+2sinθ+sin2θ+cos2θcosθ(1+sinθ)

=(1+2sin theta + sin^2 theta + 1-sin^2 theta)/(cos theta(1+sin theta))=1+2sinθ+sin2θ+1sin2θcosθ(1+sinθ)

=(1+2sin theta + cancel(sin^2 theta) + 1-cancel(sin^2 theta))/(cos theta(1+sin theta))

=(2+2sin theta)/(cos theta(1+sin theta))

=(2(1+sin theta))/(cos theta(1+sin theta))

=(2 (cancel (1+sin theta)))/(cos theta cancel((1+sin theta)))

=2/cos theta

=2*1/cos theta

=2sec theta

:.= Right Hand Side