Answer:
A = 59.63cm^2
Step-by-step explanation:
You have the following function for the surface area of the container:
[tex]A=\pi r^2+\frac{100}{r}[/tex] (1)
where r is the radius of the cross sectional area of the container.
In order to find the minimum surface are you first calculate the derivative of A respect to r, to find the value of r that makes the surface area a minimum.
[tex]\frac{dA}{dr}=\frac{d}{dr}[\pi r^2+\frac{100}{r}]\\\\\frac{dA}{dr}=2\pi r-\frac{100}{r^2}[/tex] (2)
Next, you equal the expression (2) to zero and solve for r:
[tex]2\pi r-\frac{100}{r^2}=0\\\\2\pi r=\frac{100}{r^2}\\\\r^3=\frac{50}{\pi}\\\\r=(\frac{50}{\pi})^{1/3}[/tex]
Finally, you replace the previous result in the equation (1):
[tex]A=\pi (\frac{50}{\pi})^{2/3}+\frac{100}{(\frac{50}{\pi})^{1/3}}}[/tex]
[tex]A=59.63[/tex]
The minimum total surface area is 59.63cm^2
