matalb

a. Write a user-defined function that calculates the sum of the following series for the first n terms that are determined by the user. (DON'T USE LOOPS, USE ONLY THE INFORMATION YOU ARE GIVEN IN THIS TERM) y = 3n + 121/6, n = 1,2,3,..., n b. Use the user-defined function that have written in first branch of the question, to plot the summations of the series for the interval 1 Sns 20