Can You Simplify Integrals by Separating Radicals?

[Cacophony]

Homework Statement

for the following integrals, am I allowed to break them up like so:

1. ∫(1)/(sqrt(16-9x²)³) dx

= ∫(1)/(√16)³ · ∫(1)/(√-9x²)³ dx

2. ∫(x²)/(sqrt(x²-9)) dx

= ∫(x²)/(√x²) · ∫(x²)/(√-9) dx

3. ∫(1)/(x²(sqrt(a²+x²))) dx

= ∫(1)/(x²) · ∫(1)/(√a²) · ∫(1)/(√x²) dx

? ? ?

Homework Equations

none

The Attempt at a Solution

I need to know if I'm allowed to break them up like this before I start attempting a solution

 

[eumyang]

Is this what you are writing for #1?
\int \frac{1}{\left( \sqrt{16-9x^2}\right)^3} dx
=\int \frac{1}{\left( \sqrt{16}\right)^3} dx \cdot \int \frac{1}{\left( \sqrt{-9x^2}\right)^3} dx
Yikes. No, you cannot do that!

\sqrt{a - b} \ne \sqrt{a} \cdot \sqrt{-b}
Better review the properties of radicals.

 

[Cacophony]

Ok, guess i'll try something else. Thanks