# Differential and Integral Calculus by Feliciano and Uy, Exercise 1.1 Problem 6

#### The stiffness of a beam of rectangular cross section is proportional to the breadth and the cube of the depth. If the breadth is 20 cm, express the stiffness as a function of the depth.

SOLUTION:

$S=bd^{3\:}$
$S=20d^3$