Prove that sqrt((1-cosx)/(1+cosx)) -= (1-cosx)/(|sinx|) 1cosx1+cosx1cosx|sinx| ?

2 Answers
Feb 14, 2018

Please see below.

Explanation:

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sqrt((1-cosx)/(1+cosx))=sqrt(((1-cosx)(1-cosx))/((1+cosx)(1-cosx)))=1cosx1+cosx=(1cosx)(1cosx)(1+cosx)(1cosx)=

sqrt(((1-cosx)^2)/(1-cos^2x))=sqrt((1-cosx)^2/sin^2x)=(1-cosx)/abssinx(1cosx)21cos2x=(1cosx)2sin2x=1cosx|sinx|

Feb 14, 2018

We seek to prove that:

sqrt((1-cosx)/(1+cosx)) -= (1-cosx)/(|sinx|) 1cosx1+cosx1cosx|sinx|

Consider the RHS:

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