Question 639836
The equation h=7cos[(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.
 h=7cos[(pi/3)t]
 h/7=cos[(pi/3)t]
arccos(h/7)=πt/3
t=3arccos(h/7)/π

b. Find the times at which the weight is first at a height of 1cm, of 3cm, and of 5cm.
use calculator set to radians for arccos
h=1cm
t=3arccos(1/7)/π≈1.36 sec
..
h=3cm
t=3arccos(3/7)/π≈1.08 sec
..
h=5cm
t=3arccos(5/7)/π≈0.74 sec