## anonymous 4 years ago Calculate an integral

1. anonymous

2. anonymous

Have you tried u-sub?

3. anonymous

try u = 9-x^2

4. anonymous

No, sub u=x^2

5. anonymous

I'm pretty sure mine still works... Both are fine...

6. anonymous

my substitution become like this...

7. anonymous

Well you can trig sub if you want but that makes it needlessly complicated IMO.

8. anonymous

emm what u suggest ?

9. anonymous

I told u. u = 9-x^2.

10. anonymous

Do you know how to u-sub?

11. anonymous

$u=x^2; \frac{ 1 }{ 2 }du = xdx$

12. anonymous

Again, either mine or james' work, since he keeps insisting....

13. anonymous

you will get: $\frac{ 1 }{ 2 }\int\limits_{0}^{1.6}(9-u)^{3/2}u du$

14. anonymous

for the integrand $(9-u)^{3/2}u$ sub s=9-u and ds=-du

15. anonymous

at this point you can expand the integrand and solve.

16. anonymous

@jamesHayek I msged you but I'll tell you again: We don't want to give them most of the problem.

17. anonymous

vf321, this is a site to help. Not bicker. Show your work to help her.

18. anonymous

@jamesHayek help, not do homework for. But fine, this is not getting us anywhere. Let's stop arguing.

19. anonymous

i am following ur step now. thx. trying to get the right answer

20. anonymous

i will try both method