Answer
$–3 \cos x$
Work Step by Step
The graph is the inverted graph of problem 11
which implies it is $–3 \cos x$
or by using deduction
Using general equation $y = k – A\cos (Bx + C)$
$Amplitude = |A|$
$Period = \frac{2\pi}{B}$
$Horizontal\ shift = –\frac{C}{B}$
$Vertical\ shift = k$
Period is $2\pi$ this gives B = 1
Amplitude is 3 so $A=3$
No vertical shift found as average of maximum and minimum is 0
so k = 0
The graph has
y = –3 at $x = 0, 2\pi$
y = 0, at x = $\frac{\pi}{2}, \frac{3\pi}{2}$
C = 0 as graph starts with minima
this gives graph as $–3 \cos x$
