Raymond J. answered 01/20/21
Patient with Ability to Explain in Many Ways
We have
y = C - (4)cos(x)
and y(pi/2) = 2
Putting in pi/2 we get
C - (4)cos(pi/2) = 2
Since cos(pi/2) = 0 we have
C -(4)(0) = 2
C = 2
So our original equation is y = 2 - (4) cos(x)