## Calculus 8th Edition

The critical numbers are $p=1\pm \sqrt 5$
Find the critical values of this function $h(p)=\frac{p-1}{p^2+4}$ Differentiate and set the derivative $=0$ $h'(p) = \frac{p^2+4-2p(p-1)}{(p^2+4)^2}$ Critical numbers exist where the derivative $= 0$. The derivative $= 0$ when the numerator $= 0$ $0=p^2+4-2p^2+2p$ $0=-p^2+2p+4$ Solve for $p$ with the quadratic formula $p=1\pm \sqrt 5$