[问答题]
$\text { The following diagram shows the graph of } f(x)=a \sin k x+c \text {, for } 0 \leq x \leq 16 \text {. }$
The graph of f has a minimum at $\mathrm{P}(4,8)$ and a maximum at $\mathrm{Q}(12,16)$ .
1. 1. Find the value of c .
2. Show that $k=\frac{\pi}{8}$ .
3. Find the value of a .
The graph of g is obtained from the graph of f by a translation of $\binom{d}{0} $.
The minimum point on the graph of g has coordinates (6.5,8) .
2. 1. Write down the value of d .
2. Find g(x) .
The graph of g changes from concave-up to concave-down when x=\nu .
3. 1. Find $\nu$ .
2. Hence, or otherwise, find the maximum positive rate of change of g .
