Question

Recall that a geometric sum is a sum of the form a+ar+ar^2 +ar^3 +.... (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 = 3, r = 1/2 and n = 10. (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 = 3, r = 1/2 and n = 10. 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.

Answer 1

Given, a = 3, r = 1/2, n = 10

%r is common ratio

%n is number of terms

%a is the first term of the series

Sum = 0;

a = 3;

r = 1/2;

for i = 0 : 1 : 10;

Sum = Sum + a * r ^ i;

end

Sum