grandes-ecoles 2024 Q2.2

grandes-ecoles · France · x-ens-maths-c__mp Sequences and Series Evaluation of a Finite or Infinite Sum

Prove that $$\sum _ { n = 0 } ^ { + \infty } \frac { ( - 1 ) ^ { n } } { 2 n + 1 } = \frac { \pi } { 4 }$$

Prove that
$$\sum _ { n = 0 } ^ { + \infty } \frac { ( - 1 ) ^ { n } } { 2 n + 1 } = \frac { \pi } { 4 }$$