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
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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