Question 7 (a) Verify by differentiation that
\int (x)/(2\sqrt(2+x))dx=(1)/(3)(x-4)\sqrt(2+x)+K
where
K
is a constant. [6 marks] (b) Consider the function
f(x)=x^(3)-3x^(2)
. (i) Determine the critical number(s) of
f
. [2 marks] (ii) Find the intervals where
f
is increasing. [3 marks] (iii) Find the intervals where
f
is decreasing. [3 marks] (iv) Find the local extrema of
f
. [2 marks] (v) Sketch the graph of
f
, clearly indicating the intercepts. [5 marks] (c) Use L'Hôpital's rule to evaluate
\lim_(x->3)((1)/(x)-(1)/(3))/(x^(2)-9)
[4 marks]