which graph represents: *\n1 point\ny = -3cos(3x)\na)\nb)\nc)\nd)\na\nb\nc\nd

Explanation:

Step1: Identify amplitude

The general form of a cosine - function is $y = A\cos(Bx)$. For the function $y=-3\cos(3x)$, the amplitude $|A| = | - 3|=3$. This means the maximum value of the function is 3 and the minimum value is - 3. Option D can be eliminated as its amplitude is not 3.

Step2: Identify period

The period of the cosine function $y = A\cos(Bx)$ is given by $T=\frac{2\pi}{|B|}$. For $y=-3\cos(3x)$, $B = 3$, so the period $T=\frac{2\pi}{3}$. Option A has a period of $2\pi$ and can be eliminated.

Step3: Consider the negative sign

The negative sign in front of the cosine function $y=-3\cos(3x)$ reflects the graph of $y = 3\cos(3x)$ about the x - axis. Option B is the graph of $y = 3\cos(3x)$ (it starts at the maximum value), while option C is the graph of $y=-3\cos(3x)$ (it starts at the minimum value).

Answer:

C