Question

How do you evaluate the definite integral `int x^(3) dx` from `[b, 2b]`?

Answer 1

I found: `15/4b^4`

Explanation:

You get:
`int_b^(2b)x^3dx=[x^4/4]_b^(2b)`
`=1/4((2b)^4-b^4)=1/4(16b^4-b^4)=15/4b^4`