# Math Help - Double Integral help

1. ## Double Integral help

What ive done:

(-1, 2)
(1, 2) are the intercepts.

my integral has dy then dx.
1top -1bottom on the outside integral.
(x^2 + 1)top (2x^2)bottom on the inside integral.

****

So i got 8/15 units^2 just wondering if this is right, if not pls help.

2. ## Re: Double Integral help

Hey Brennox.

One method for future ref erence to check symbolic calculations is to use Wolfram Alpha which is a symbolic computational engine. You should put your integral in there to see how it turns out:

Wolfram|Alpha: Computational Knowledge Engine

This is especially useful if you can't find someone quick enough.

3. ## Re: Double Integral help

Originally Posted by Brennox

What ive done:

(-1, 2)
(1, 2) are the intercepts.

my integral has dy then dx.
1top -1bottom on the outside integral.
(x^2 + 1)top (2x^2)bottom on the inside integral.

****

So i got 8/15 units^2 just wondering if this is right, if not pls help.
I agree with your bounds. I don't agree with your final answer. Unless you post all your working, I can't see where you've gone wrong.

4. ## Re: Double Integral help

Originally Posted by Prove It
I agree with your bounds. I don't agree with your final answer. Unless you post all your working, I can't see where you've gone wrong.
okay i got it arithmatic error, can you have a look at this other question please

Line integral Question

5. ## Re: Double Integral help

did you get 16/15? it's really an easy integral

6. ## Re: Double Integral help

I got 16/15 as well.

7. ## Re: Double Integral help

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8. ## Re: Double Integral help

I'm curious how one visualizes a 4 dimensional object for a quadruple integral where the planes are 3d surfaces- like you can it seems deduce properties of a 4D cube.
there was an interesting amplituhedron discovery lately in 4 dimensions