fake quote> Anyone that took a Calculus course knows how to analyze this function and get the minimum, maximum and increasing and decreasing intervals. The calculation is unsurprising and boring, so I will skip it and use a graph instead.

fake quote> Anyone that didn't take a Calculus course will not understand the technical details. The calculation is long enough to be distracting and boring, so I will skip it and use a graph instead.

Unless the main public of the blog are students from the first year of the university, I agree with the author that it's better to use a graph and left the calculations as an exercise.

[Perhaps the analytical calculation could have been a note at the bottom, but it's long and unsurprising enough to be boring to write it clearly and carefully. Just left it as an exercise :) .]