Thomas algorithm (Numerical methods)

Question

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Please help i've been trying to solve it since 2 days.I have solved it using the differential equation but answer is coming different from thomas algo. and DE.

Answer 1

Please note that Thomas algorithm is just an improved way of applying Gaussian elimination to a tridiagonal linear system. With such a huge value for $\Delta x$ you will necessarily get big errors with respect to the exact solution (unless the exact solution is a polynomial with degree $\leq$ than the precision of the finite difference formulas being used).

If you implemented the problem in matlab or equivalent, just run your code for smaller and smaller $\Delta x$ and observe if the numerical solution is approaching the exact solution.