Question #58780

2 Answers
Nov 1, 2017

#RHS=(sin^2x)/(2+sin2xcscx)#

#=(2sin(x/2)cos(x/2))^2/(2+2sinxcosx xx1/sinx)#

#=(4sin^2(x/2)cos^2(x/2))/(2(1+cosx ))#

#=(4sin^2(x/2)cos^2(x/2))/(2*2cos^2(x /2))#

#=sin^2(x/2)=LHS#

Nov 1, 2017

Formulas to be used in the proof.

  1. #sin 2x = 2 sin x cos x#

  2. #sin (1/2 x)=+-sqrt((1-cosx)/2)#
    #:.sin ^2(1/2 x)=(1-cosx)/2#

  3. #cscx=1/sinx#
  4. #sin^2x+cos^2x=1#
    #sin^2x=1-cos^2x#

Right Hand Side:

#sin^2x/(2+sin2xcscx)=sin^2x/(2+2sinx cosx cscx)#

#=sin^2x/(2+2cancelsinx cosx * 1/cancelsinx)#

#=(1-cos^2x)/(2+2cosx )#

#=((1-cosx)(1+cosx))/(2(1+cosx ))#

#=((1-cosx)cancel(1+cosx))/(2cancel(1+cosx ))#

#=(1-cosx)/2#

#=sin^2(1/2)x#

#:.=#Left Hand Side