My first ode doesn't converge.

Hello,

I'm trying to solve this ordinary differential equation numerically by using runge kutta 4 , but the solution won't converge unless i reduce the value of parameter c by multiplying it with the factor f, even when try i reduce the time step the problem is still there, i've been struggling with this problem for day and i really appreciate if any one can help me.

[Ameer Hamza]

Please don't add duplicate questions: https://www.mathworks.com/matlabcentral/answers/514617-i-m-trying-to-solve-this-system-of-ode-with-runge-kutta-4-but-the-solution-doesn-t-converge?s_tid=prof_contriblnk