Please do numbers 3 and 4

Problem 1. (20 Points) The sum of a finite geometric sequence can be expressed using the formula: ar" - a S = a tartars + ... + arr- ] = r- 1 1. (5 Points) Show that the equality above holds. 2. (5 Points) Use the same method to show that sni = (Ity-1 i 3. (5 Points) Write down the annuity Snap; in geometric sequence form. 4. (5 Points) Using the methods used so far, show that Snap; = Smi(1 +i) + ski