Valumptious5115 Valumptious5115 23-05-2023 Mathematics contestada 1. Consider the formula for the surm of a geometric series: C Σαν"-1 -, 1-Y n1 Derive this formula by using the nth partial sum Sn. Hint: Subtract SN-r. Sn 2. Show that Σ" - Σ" - Σετ - Σ cr C