Question #448ec

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Answer 1 · 2017-11-13T15:26:00

#LHS=sqrt(2+sqrt(2+2cos4x))#

=#sqrt(2+sqrt(2(1+cos4x))#

=#sqrt(2+sqrt(2*2cos^2(2x)#

#=sqrt(2+sqrt(4cos^2(2x))#

=#sqrt(2+2cos2x)#

=#sqrt(2(1+cos2x))#

=#sqrt(2*2cos^2x)#

=#sqrt(4cos^2x)#

#=2cosx#

#=RHS#