# Thread: Volume of a solid

1. ## Volume of a solid

What is the volume of:
y=square root(x), y=1, x=4

2. Use the disc method. We create a disc by making a cross section perpendicular to the x-axis. The volume is then given by $\int_a^b A(x) dx$ where $A(x)$ is the area of our disc and $x= a, \ b$ are our bounds.

More here: Volume with Rings

3. is that the same as
V=(pie)interval from a to b((f(x)^2)-(g(x)^2) dx

4. Yes. What is our $f(x)$ and $g(x)$ in this case?

5. f(x)=square root of x
g(x)=1

6. So is the answer 9pie/2

7. awesome thanks

8. Also see picture