A$)$ Write a Fortran program to consider the differential equation dy$/$dx$=$x$^3+2$x$,$ where y $(0)=1.$ Assume h $=0\mathrm{.}5.$ Use Euler$$s method to determine values of y$($x$)$ in the interval $[0,3].$ For each value, calculate the difference between your Euler method solution and the exact function y $($x$).$ Using gnuplot, plot this difference for the x values in the interval $[0,3].$ Attach a screenshot of the code and the results from running the code.

B$)$ Repeat part $($A$)$ but set h $=0\mathrm{.}05.$ Attach a screenshot of the code and the results from running the code.