Chapter 6.5, Problem 20ES

True-False Determine whether the statement is true or false. Explain your answer.

The expression

${\displaystyle \underset{k=1}{\overset{n}{\sum }}2\pi f\left(x_k^{**}\right)}\sqrt{1+\left[f^{\prime }\left(x_k^{*}\right)\right]}\Delta x_k$

is not a true Riemann sum for

${\displaystyle {\int }_a^{b}2\pi f\left(x\right)\sqrt{1+{\left[f^{\prime }\left(x\right)\right]}^2}dx}$