Answers:
- Amplitude = 2
- Period = 5pi/2
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Explanation:
The lowest point occurs when y = -2. The highest point occurs when y = 2.
The vertical distance between the highs and lows is 4 units (since 2-(-2) = 2+2 = 4). This cuts in half to get 4/2 = 2.
The amplitude is 2. It measures the vertical distance from the midline to either the peaks or valleys.
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Note that this curve has two lowest points and one highest point shown. What we'll do is shift the graph over to the right so that each of those lowest points snap to a grid point. The lowest point on the left will move to where x = -pi, while the lowest point on the right snaps to x = 3pi/2. We'll keep each point at the same y coordinate.
The horizontal distance from x = -pi to x = 3pi/2 is
(3pi/2) - (-pi) = 3pi/2 + 2pi/2 = 5pi/2
This represents the horizontal distance from the left valley point to the right valley point. This is one full period of the curve. After we arrive at the right valley point, we repeat the process of going up and coming back down in this exact same fashion. The process is repeated forever to generate the cosine curve. The curve repeats itself every 5pi/2 units along the x axis.
Side note: any phase shift of a curve will have the same period as the original curve. This is why we're allowed to shift left or right to help find the period.
