Surface area inside an elliptic cylinder

MasterWu77
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Homework Statement



Find the surface area of that part of the plane 8x+3y+z=9 that lies inside the elliptic cylinder (x^2/64) + (y^2/9) =1

Homework Equations



not sure what equations i need to use. probably parametrization of a region

The Attempt at a Solution



i'm not quite sure how to start this problem. how do i related the elliptic cylinder with the plane?
 
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Hi MasterWu77! :smile:

You could just say it's a projection, and divide the base area of the cylinder by the appropriate cosine. :wink:
 
ok but how would i say that it is a projection and what exactly do you mean by the appropriate cosine?
 
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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