Philipp
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### Questions (8)

 6 Prove $\sum_{k=1}^nk^3=\sum_{n=1}^n\sum_{j=}^nk\cdot j$ 3 limit for $a_n=\frac{n}{3^n}$ 2 Is $\sum_{k=1}^n\sum_{j=1}^nk\cdot j=\sum_{k=1}^nk\cdot\sum_{j=1}^nj$? 1 Proof for for convergence of $\int_{-∞}^0\frac{\sqrt{\left|x\right|}}{x^2+x+1}dx$ 0 finding the limit of $a_n=\sqrt[3]{n}\cdot\frac{\sin n}{\sqrt{n+1}}$

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 1 Prove $\sum_{k=1}^nk^3=\sum_{n=1}^n\sum_{j=}^nk\cdot j$

### Tags (12)

 1 summation × 3 0 limits 1 induction × 2 0 real-analysis 0 sequences-and-series × 2 0 analysis 0 trigonometry 0 complex-numbers 0 integration 0 definite-integrals

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