Chapter 6.4, Problem 10ES

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

The approximation

$L\approx {\displaystyle \underset{k=1}{\overset{n}{\sum }}\sqrt{{\left(\Delta x_k\right)}^2+{\left[f\left(x_k\right)-f\left(x_{k-1}\right)\right]}^2}}$

for arc length is not expressed in the form of a Riemann sum.