Integrating f(x,y,z): Confirm Ranges for x, y, z

  • Thread starter Thread starter naspek
  • Start date Start date
  • Tags Tags
    Integrating
naspek
Messages
176
Reaction score
0

Homework Statement



f(x, y, z) = x^2 ; G is tetrahedron bounded by the coordinate planes and the plane octant with equation x + y + z = 1

∫ ∫ ∫ x^2 dzdydx

I try to set up the ranges for x, y and z..

x+y+z = 1
z = 1-x-y...set the limits for z from z=0 to z = 1-x-y

x+y+z = 1
if, z = 0, y = 1-x ...set the limits for y = 0 to y = 1-x

x+y+z = 1
if, z = 0 , y = 0 ...x = a set the limits from x = 0 to x =1

first.. i need help to confirm that my ranges are correct..
because.. I've done the integration and got the wrong answer..
i've double checked my integration and it is right..
there must be something wrong with my ranges.. i guess...
 
Physics news on Phys.org
They look right to me. Why don't you show what you did. It may be an integration error.
 
yup2.. it's integration error.. duuhh...~
thanks btw..
problem solved..
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
Back
Top