Complex sentence: For example, if the function is not "infinitely differentiable", one cannot generate a Taylor series-and many functions which are infinitely differentiable have higher order derivatives that are unmanageable by hand.
Split into simpler sentences: For example, if the function is not "infinitely differentiable", one cannot generate a Taylor series. Many functions which are infinitely differentiable have higher order derivatives that are unmanageable by hand.