I ploted a few numeric approximations of the equation $y'=2 \cos x - x^2 y - 1$ with the Runge-Kutta method using different h values.
Now I need to evaluate the errors for these different plots and I'm having difficulties doing so as I can't find an analytical solution for the equation to compare my values to. Would love to get some help in solving the equation analyticly or for an alternative way to evaluate the error.
