Select the correct answer.

The rod on a pump rises and falls as the pump operates. The following function gives the height of the top of the rod above the pumping unit in feet, [tex]L(t)[/tex], as a function of time in seconds, [tex]t[/tex], after the pump is activated.

[tex]\[
L(t) = \frac{3}{2} \sin \left( \pi t + \frac{\pi}{2} \right) + \frac{3}{2}
\][/tex]

What is the period of the given function?

A. 4 seconds
B. 3 seconds
C. 2 seconds
D. 1 second



Answer :

To determine the period of the given function, we need to analyze the characteristics of the sine function within it. The given function is:
[tex]\[ L(t) = \frac{3}{2} \sin \left(\pi t + \frac{\pi}{2}\right) + \frac{3}{2} \][/tex]

Let's recall the general form of a sine function:
[tex]\[ f(t) = A \sin(Bt + C) + D \][/tex]
where:
- [tex]\( A \)[/tex] is the amplitude,
- [tex]\( B \)[/tex] is the coefficient that affects the period,
- [tex]\( C \)[/tex] is the phase shift, and
- [tex]\( D \)[/tex] is the vertical shift.

The period [tex]\( T \)[/tex] of a sine function is determined by the coefficient [tex]\( B \)[/tex] inside the sine function:
[tex]\[ T = \frac{2\pi}{B} \][/tex]

In the given function, we identify that:
[tex]\[ B = \pi \][/tex]

Substituting [tex]\( B = \pi \)[/tex] into the formula for the period, we get:
[tex]\[ T = \frac{2\pi}{\pi} \][/tex]

The [tex]\( \pi \)[/tex] terms cancel out, simplifying to:
[tex]\[ T = 2 \][/tex]

Therefore, the period of the given function [tex]\( L(t) \)[/tex] is [tex]\( 2 \)[/tex] seconds.

Hence, the correct answer is:
2 seconds