Plot the graph of the function $y=f(x)$ where $f(x) = x(x+|x|)$.
Find the first and second derivatives of the function. Show that
the first derivative exists at $x=0$ but that the second derivative
does not exist at $x = 0$.
NOTES AND BACKGROUND
This is a very simple question but it requires an understanding of
how to handle functions that are defined differently on different
parts of their domains.
Show without recourse to any calculating aid that 7^{1/2} + 7^{1/3}
+ 7^{1/4} < 7 and 4^{1/2} + 4^{1/3} + 4^{1/4} > 4 . Sketch
the graph of f(x) = x^{1/2} + x^{1/3} + x^{1/4} -x