EA

d$2$u

dx$2=$p$($x$)$:

$$ Derive the governing equation for the displacement u$($x$)$ of the bar assuming E $=$ E$($x$)$

and A $=$ A$($x$)$ can change with position. Hint: the answer is not E$($x$)$A$($x$)$ d$2$u

dx$2=$p$($x$).$

Recall the force balance equation from lecture.