`1+i^2+i^4+i^6+i^8++i^(20)` – InterviewSolution

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1.	`1+i^2+i^4+i^6+i^8++i^(20)`
Answer» This is a GP in which a = 1, `r = i^(2) = -1` and n = 11. `therefore" "S=(a(1-r^(n)))/((1-r))=(1xx{1-(-1)^(11)})/({1-(-1)})=(2)/(2)=1`.

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