Prove that sqrt((1-cosx)/(1+cosx)) -= (1-cosx)/(|sinx|) ?

2 Answers
Feb 14, 2018

Please see below.

Explanation:

.

sqrt((1-cosx)/(1+cosx))=sqrt(((1-cosx)(1-cosx))/((1+cosx)(1-cosx)))=

sqrt(((1-cosx)^2)/(1-cos^2x))=sqrt((1-cosx)^2/sin^2x)=(1-cosx)/abssinx

Feb 14, 2018

We seek to prove that:

sqrt((1-cosx)/(1+cosx)) -= (1-cosx)/(|sinx|)

Consider the RHS:

RHS = (1-cosx)/(|sinx|)

\ \ \ \ \ \ \ \ = sqrt( ((1-cosx)/(|sinx|))^2 )

\ \ \ \ \ \ \ \ = sqrt( (1-cosx)^2/(sin^2x) )

\ \ \ \ \ \ \ \ = sqrt( (1-cosx)^2/(1-cos^2x) )

\ \ \ \ \ \ \ \ = sqrt( (1-cosx)^2/((1+cosx)(1-cosx) )

\ \ \ \ \ \ \ \ = sqrt( (1-cosx)/(1+cosx) )

\ \ \ \ \ \ \ \ = LHS \ \ \ \ QED