Which image shows 1 7/8 on a number line?

Use the function nest to evaluate p(x) = 1 + x + · · · + x50 at x = 1.00001. (use the matlab ones command to save typing.) find the error of the computation by comparing with the equivalent expression q(x) = (x51 − 1)/(x − 1).

How to do this , and can some one explain

What is the inverse of the function f(x) = 2x + 1?