How to Implement FEM with a Discontinuity in the Exact Solution?

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Homework Statement



Use FEM to solve this problem. The difficulty lies in the fact that the exact solution has a discontinuity in it. From x=[0,0.6) the exact solution u is x5/20 - x/20 and from x =(0.6,1] u is sin(x). The problem I'm having is I'm not sure what to do at the jump in my code. I have already set up my matrices Au = f, and it solves it fine given no discontinuity.

uxx = f

Homework Equations



u(0) = u0
u(1) = u1
 
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ageralo said:

Homework Statement



Use FEM to solve this problem. The difficulty lies in the fact that the exact solution has a discontinuity in it. From x=[0,0.6) the exact solution u is x5/20 - x/20 and from x =(0.6,1] u is sin(x). The problem I'm having is I'm not sure what to do at the jump in my code. I have already set up my matrices Au = f, and it solves it fine given no discontinuity.

uxx = f

Homework Equations



u(0) = u0
u(1) = u1

What is FEM?

RGV
 
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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