Something’s not working the way it seems like it should.

When I type the following formulas

{

f(x) = e^rx

g(x) = f’’(x)-2f’(x)-3f(x)

}

I saw wrongs values on the graphic, starting at x=10 its very clear that the function return values that are wrong, it should be 0 for all values of x, when r=3, actually g(x) is equal to zero when r = -1 and r=3 (when r=-1 the values of the graphic are correct)

here are some screenshots