How to Approach Proving a Partial Derivative Homework Problem?

xortan
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Homework Statement


I have attached a picture of the problem. The question is the first one.


Homework Equations





The Attempt at a Solution


I tried subbing u and v into the right hand side of the equation. I expanded and simplified but I do not think that is the right way to go about it. If somebody can point me in the right direction that would be very helpful. Thank you!
 

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hi xortan! :wink:
xortan said:
I tried subbing u and v into the right hand side of the equation.

my guess is that it's quicker to start from the left hand side

(you could also "factor" it into (∂/∂x + ∂/∂y)(∂/∂x - ∂/∂y)z)

… show us what you get :smile:
 
Well I am really new at partial derivative, we just started this course. Was doing a single variable calc course last semester and only touched on this stuff briefly at the end. I am not understanding where to go when starting from the left hand side. I asked another one of my instructors and he showed me this "brute force" way of doing it. I got it to a point of



(∂2z/∂x2 = (∂/∂x)(∂z/∂u)2x + ∂z/∂u * 2 + (∂/∂x)(∂z/∂v)2y

I got to deal with the first term now but the question seems to be blowing up and I know there has to be an easier way of doing this
 
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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