As h approaches zero
I quietly despair.
It really is the limit.
Please don’t take me there.
The funny thing about the calculus is that it was brought into existence by Isaac Newton in 1666 or earlier, and was developed and used without the idea of limits for over 150 years. The first attempt to get rid of the troublesome infinitesimals was by Cauchy in 1821, where he introduced the chord slope (f(x + h) – f(x))/h. The whole business of finding a satisfactory definition of the derivative was finally achieved by Weierstrass in the mid 19th century.
So here we go with cubics, and the same approach can be used for any whole number power of x, even negative ones. You should try it.
Next time sin(x) and cos(x), so no more sin(h)/h stuff.