As it happens you don't need to, at the command prompt now type:

If you want them on the same plot you will needCode:`>>plot(x,(f(x+0.1)-f(x))/0.1,'r')`

>>plot(x,(f(x+0.01)-f(x))/0.01,'g')

>>plot(x,(f(x+0.001)-f(x))/0.001,'b')

>>plot(x,(f(x+0.0001)-f(x))/0.0001,'m')

before hand, (and sort out axes)Code:`>>hold on`

CB