What is the minimum of the sinusoidal function?

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Step-by-step explanation:

The amplitude of a sinusoidal function is one-half of the positive difference between the maximum and minimum values of a function. It is simply the vertical distance from the x-axis (or midline) to the highest (or lowest) point on the curve.

step-by-step explanation:

points a and b are equidistant from the desired line, so the line you find by using them will go through point r.

using points other than a and b will give the desired line only if they are equidistant from r. if they are randomly located, the perpendicular line you create will not necessarily go through point r, hence will not be a solution to the problem.