Drawing the graphs first will greatly aid in their
interpretation!
Key to this problem is the idea for small values of $t$ we have $t$
is a lot larger than $t^2$, which is in turn a lot larger than
$t^3$. For large values of $t$ the reverse is
true.
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