Is My Solution for the Triple Integral Correct?

mathzeroh
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Triple Integral Evaluation (quick and easy)

Homework Statement


<br /> \int_{0}^{1} \int_{x^2}^{1} \int_{0}^{3y} ({y+2x^2z})dz dy dx<br />


Homework Equations



None.

The Attempt at a Solution



Here is what I got at the end (the LaTeX takes too long to code in here, plus its not showing up):

59/36 because after integrating the whole thing, and then putting in the very last limits (0 and 1), all of the x's go away leaving just the coefficients which I worked out to get 59/36...can someone please verify this for me? I've checked it twice and got the same solution..it takes about 3 minutes to do if you're a genious (unlike me, so I'm trying to appeal to the math geniuses)..

thanks!
 
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I get (actually Maple) \frac{32}{21}

∫{0}^{3y}(y+2x²z)dz= 9x²y²+3y²

∫_{x²}^{1}( 9x²y²+3y²)dy= -3x^{8}-x^{6}+3x²+1



∫_{0}^{1}(-3x^{8}-x^{6}+3x²+1) dx= ((32)/(21))
 
did it by hand and got 32/21
 
I did it by hand, too. :-p I had to type everything and then use the "ctrl c-ctrl v" keys. It's not as easy as it seems...:biggrin:

Daniel.
 
\int_0^1\int_{x^2}^1\int_0^3y (y+ 2x^2z)dzdydx
\int_0^1\int_{x^2}^1\left[yz+ x^2z^2\right]_0^{3y}dydx
3\int_0^1\int_{x^2}^1(1+ x^2)y^2 dy dx
\int_0^1\left[(1+3x^2)y^3\right]_{x^2}^1 dx
\int_0^1(1+3x^2)(1-x^6)dx
\int_0^1(-3x^8- x^6+ 3x^2+ 1)dx
\left[-\frac{1}{3}x^9-\frac{1}{7}x^7+ x^3+ x\right]_0^1
-\frac{1}{3}-\frac{1}{7}+ 1+ 1
-\frac{7}{21}-\frac{3}{21}+\frac{21}{21}+\frac{21}{21}
\frac{32}{21}
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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