So they give me the problem, and then some sample code to help, but im still not understanding this...

I realize I need a seperate M-file script called geo_sum that we call in to do the for loop, but what exactly is in the for loop?

Please explain, thank you!

EXERCISE 2 Recall that a geometric sum is a sum of the form aar+ar2 + ar3 + (a) Write a function file that accepts the values of r, a and n as arguments and uses a for loop to return the sum of the first n terms of the geometric series. Test your function for a = 5, r = 1 /3 and n 8 b) Write a function file that accepts the values of r, a and n as arguments and uses the built in command sum to find the sum of the first n terms of the geometric series. Test your function for a 5,1/3 and n-8. Hint: Start by defining the vector e=0 :n-1 and then evaluate the vector R = r e. It should be easy to figure out how to find the sum from there