Mathematics · 2025
JEE Main · 4 April 2025, Shift 2 · Q21
If α is a root of the equation x^2+x+1=0 and Σ_k =1^n (α^k +1/(α^k))^2=20, then n is equal to ____.
If $\displaystyle \alpha$ is a root of the equation $\displaystyle x^2+x+1=0$ and $\displaystyle \sum_{\mathrm{k}=1}^{\mathrm{n}}\left(\alpha^{\mathrm{k}}+\frac{1}{\alpha^{\mathrm{k}}}\right)^2=20$, then n is equal to
$\displaystyle \_\_\_\_$.
Official answer
From NTA’s final answer key for this paper.
11
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JEE Main 2025 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.