When graphing, you should use www.desmos.com (an online graphing calculator). Type the equation in on the left hand window, and click on settings to set the x-min/x-max, y-min/y-max.

Graph these two surface area functions and try to see if they line up

SA=677.4r^-1+2pir^2

SA'=-677.4r^-2+4pir

*idk how to make the graph on desmos look like this

Calculus Cans Optimization PT 800 pringles pizza.pmy 600 SA = 2180. 625 + 27172 400 200 SA = - 2180. 6 25 + 4017 0 10 15