I need help with this difficult sinosoid problem?

Question

The Reflector on a bicycle wheel is 15cm from the rim. The diameter of the wheel is 76cm at time = 1/2 sec, the reflector is at its lowest point; 3/4 sec later it returns to the same position.Find an equation which will locate the height of the reflector above the ground at any time t.

a) Find height when t=5.2 sec
b) Find the 1st time the reflector is at a height of 59cm above the ground

Can u help me find the equation i have one but i dont know if its correct

Equation- y = -23 Cos [ 2pi/.75(x-.5)]+38
can u comfirm this? plz so i can calculate a & b

Answer 1

Your equation is correct. You should get:
a) 16.988cm
b) 0.32485sec