An integral

[jebem]

(09-06-2014 04:24 PM)lrdheat Wrote:  How do I get the integral from 0 to 6 for (3 root x)^2 * 3 root (6-x) to evaluate in CAS? It comes back with an integral. Approx returns the correct numerical result. My old TI NSpire CAS returns the correct (8*pi*sqrt 3)/3.

I tried on CAS mode and it returns (1/5)*sqrt(6)*1296 and in approx mode it gives 634.907741329

In wolframalpha returns (1296*sqrt(6))/5 and in approx mode the result is 634.91
www.wolframalpha.com

I also tried in Home mode and the result is the same (634.907741329).
The only difference is that in Home mode I used uppercase "X", while in CAS i used lowecase for "x".

So it seems it is alright to me.

EDIT:
I see what do you mean now:
integral from 0 to 6 for (cubic root x)^2 * cubic root (6-x)

Trying this 2nd equation in Home mode the approx answer is: 14.5103949139

And in CAS mode, I get a message: "Temporary replacing surd/NTHROOT by fractional powers"
Pressing ENTER i get another integral as you mentioned in the OP, instead of the expected (8*pi)/sqrt(3)
Trying the approx the answer is 14.5103949139