## anonymous 4 years ago This exercise is in a section about using trig substitution to integrate. I can use trig sub, but I'm just not seeing what initial substitution to use so I can apply trig sub. Can anyone give me a hint? I don't need (don't want) it solve to the end. At least not yet.

1. anonymous

See attached

2. anonymous
3. anonymous

The trick is, how do we get this integral into the form$dx \over \sqrt{u^2 +a^2}$

4. anonymous

sorry du on top

5. anonymous

note, 16+x^6= (4)^2+(x^3)^2. or (x^3)^2+(4)^2.

6. anonymous

what will be the a ? and what will be the u?

7. anonymous

then, get the derivative of u.

8. anonymous

Thanks, that is just what I needed.

9. anonymous

most welcome:))