value of n

\hspace{-16}\bf{\mathbb{C}}$alculate Integer value of $\bf{n}$ in \\\\\\ $\bf{\frac{1}{i}+\frac{2}{i^2}+\frac{3}{i^3}+.........+\frac{n}{i^n}=405}$

1 Answers

262

Aditya Bhutra ·2012-05-03 23:50:01

LHS = 1-3+5-7 ....i - (2-4+6-8.....)

now RHS is real thus LHS should also be real .

or (1-3)+(5-7) ..... + (2k+1)=0

or (-2) + (-2) + .... +2k+1 =0

which is not possible

hence no value of n

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