Question: x,y ,z are real numbers such that summation of cos x=0=summation of sinx. Prove that summation of (x*2^n)=0=summation of sin(x*2^n) for all n____>natural no.s

Dear student,

In this case apply the Arithmetic sum of sine series as well as cosine series which you have learnt in complex numbers or go thru ML Khanna

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