Mathematics · 2016
JEE Main · 10 April 2016, Shift 1 · Q63
Let z=1+a i be a complex number, a>0, such that z^3 is a real number. Then the sum 1+z+z^2+…..+z^11 is equal to:
Let $\displaystyle z=1+a i$ be a complex number, $\displaystyle a>0$, such that $\displaystyle z^3$ is a real number. Then the sum $\displaystyle 1+z+z^2+\ldots . .+z^{11}$ is equal to :
Official answer
(4)
$\displaystyle -1365 \sqrt{3} i$
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JEE Main 2016 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.