Question: How to plot the derivate of a numerical solution?


I have this differential equation:

deq := (diff(y(x), x, x))*y(x)-1+x*y(x)^2 = cos(x);

sol := dsolve({deq, y(0) = 1, (D(y))(0) = 1}, numeric);

After that I have a numerical solution for y, and for diff(y(x),x). But I would like to plot diff(y(x),x,x). (and then diff(y(x),x,x)+diff(y(x),x)*cos(x)). How can I do that?

Any help will be appreciated,


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