2019 Nov P2 Q6

Question 6

In the diagram, the graphs of $f(x)=\sin x-1$ and $g(x)=\cos 2x$ are drawn for the interval $x\in[-90^{\circ}\,;\,360^{\circ}]$ . Graphs $f$ and $g$ intersect at $A$ . $B(360^{\circ}\,;\,-1)$ is a point on $f$ .

$6.1$	Write down the range of $f$ .	$(2)$
$6.2$	Write down the values of $x$ in the interval $x\in[-90^{\circ}\,;\,360^{\circ}]$ for which graph $f$ is decreasing.	$(2)$
$6.3$	$P$ and $Q$ are points on the graphs $g$ and $f$ respectively such that $PQ$ is parallel to the $y$ -axis. If $PQ$ lies between $A$ and $B$ , determine the value(s) of $x$ for which $PQ$ will be a maximum.	$(6)$
		$\textbf{[10]}$