Seperable Partial Differential Equation

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Homework Statement



u_{x}=u_{y}+u

Homework Equations



Separation of variables

The Attempt at a Solution



It reduces to \frac{X'}{X}=\frac{Y'}{Y}+1

My question is does the 1 change at all how I use \lambda^{2}? In other words, will my solution still break down into this:

Case 1: \lambda^{2}=0

\frac{X'}{X}=0 and \frac{Y'}{Y}+1=0

Case 2: -\lambda^{2}

\frac{X'}{X}=-\lambda^{2} and \frac{Y'}{Y}+1=-\lambda^{2}

Case 3: \lambda^{2}

\frac{X'}{X}=\lambda^{2} and \frac{Y'}{Y}+1=\lambda^{2}
 
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This is correct although normally for first order PDEs, we use the method of characteristics.
 
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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