Question

Optimization Calculus Problem!

I don't get how they got the cubed root. Please explain. Much appreciated

Answer 1

2s -5488/s^2 = (2s*s^2)/s^2 -5488/s^2 = (2s^3-5488)/s^2
Since this thing is = 0,
0 multiply by its denominator is still 0
So 2s^3 - 5488 =0
s^3= 5488/2= 2744
s= cube root 2744


its alot if mental sum so they dont show step by step