Question

Please help me for part c how to do part c of this questions
The equation h = 7 cos (pi/3 t) models the height h in centimeters after t seconds of a weight attached to the end of a spring that has been stretched and then released.

a. Solve the equation for t.
b. Find the times at which the weight is first at a height of 1 cm, of 3 cm, and of 5 cm above the rest position. Round your answers to the nearest hundredth.
c. Find the times at which the weight is at a height of 1 cm, of 3 cm, and of 5 cm below the rest position for the second time. Round your answers to the nearest hundredth.

Answer 1

you have 2 values...

1. the weight going down.

2. the weight returning up.

there is a 3rd quadrant angle where

\[(\frac{\pi}{3}t) = \cos^{-1}(\frac{1}{7})\]

so remember that 3rd quadrant

\[\pi + \theta \]