2-72. Express the given series using sigma notation, then evaluate the sums with your program
or by hand,
a.
4 + 8 + 12 + 16 + 20

The input to the function is x and the output is y. write the function such that x can be a vector (use element-by-element operations). a) use the function to calculate y(-1.5) and y(5). b) use the function to make a plot of the function y(x) for -2 ≤ x ≤ 6.