Question

Can someone tell me if I did this double integral right?

Answer 1

Ok, the problem is evaluate the integral taking Ω: 0 less than/equal to x less than/equal to1, 0 less than/equal to y less than/equal to 4:

Double integral of Ω4xy^2 dxdy

First I took the integral of 4x dx from 0 to 1 and I got 2x^2, I did 2(1^2)-2(0^2) and I got 2y^2.
So then I took the integral of 2y^2 from 0 to 4 and I got (1/3)(2)y^3, which is (2/3)y^3 and then I did (2/3)4^3 - (2/3)0^3 and I got (2/3)(64) which is 128/3.

but my answer choices are;

a) 64
b)140/3
c) 0
d) 42
e) none of the above

so I think I did something wrong or the answer is none of the above. Please help!

Answer 2

I got teh same thing you did, maybe it is a typo on the test for answer b

Answer 3

actually none of the above

Answer 4

oh, ok thanks, the answer none of the above then.

Answer 5

yes