Double Integrals over General Region

zm500
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Homework Statement



Find the Volume of the given solid
Bounded by the cylinders y^2+z^2=4 and x=2y, x=0,z=0 in the first octant

Homework Equations


double integral over a region D with f(x,y) dA

The Attempt at a Solution


I graphed it in a xyz plane and got these intervals
D = {(x,y)| 0\leqx\leq4;x/2\leqy\leq2}

where f(x,y) = \sqrt{}4-y^2 with respect to dydx

I don't know how to integrate this!
 
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You could try integrating in reverse order, if that would help. If not, just try a substitution, like y=2sin(u).
 
Thank You Very Much.
Reversing order did the trick.
 
Have a great day!
 
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...
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