SIR, PLEASE HELP ME.

Asked by  | 28th Dec, 2009, 07:14: PM

Expert Answer:

cos2(x+π/3) = (cos(x+π/3))2

=(cosx cosπ/3 - sinx sinπ/3)2

=((1/2)cosx - (3/2) sinx)2

Therefore,

cos2x + ((1/2)cosx- (3/2)sinx)2 + ((1/2)cosx + (3/2) sinx)2

= cos2x + (1/2)cos2x + (3/2)sin2x 

= (3/2)(cos2x + sin2x)

= 3/2

Regards,

Team,

TopperLearning.

Answered by  | 28th Dec, 2009, 11:05: PM

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