Analytical graph not in sync with numerical graphs

The graph i got comparing an analytical solution to numerical solution is attached

<<

>>

. However, the correct graph is the one where the graphs are in sync, unlike the one i got. How do i edit my code to get the correct graph? Thanks a lot.

[Ameer Hamza]

This does not seem to be a problem with MATLAB but with your equations. I could not find any MATLAB function, which could be producing approximation error.