Solve A=2(pi)r2+2(pi)rh for h and state any excluded values

Question

Solve A=2πr²+2πrh for h and state any excluded values

Answer 1

This is the surface area of a cylinder...

 

A=2πr²+2πrh         subtract 2πr² from each side

A - 2πr² = 2πrh      divide both sides by 2πr

 

(A - 2πr²)/(2πr) = h

 

In order to have a cylinder in the first place we must

have a radius greater than zero.  r>0.  The radius must

be a positive value.

The excluded values are  r≤0