There is something wrong about the stated height: The function is never any where near 15 meters. Maybe, it's cm and you are looking for y = .15 m. Anyway,...
I would find the x values in the interval 0 to 60 seconds in which x* leads to this y* height specified. Let's say this happens at x1 and x2 only. In that case x2-x1 is the time spent over that height because you start below the height. If there are n sets of x1 and x2, the tmie above will be n(x2-x1) and, if there is no matching x2 at the end, then the time will be n(x2-x1) + 60- x*.
Good luck.
Luhan E.
by using the equations I wrote under06/02/20

JACQUES D.
06/02/20
Luhan E.
So for cos this is my equations actually f(X)= 0.255 cos(π/50(x))+0.325 so when I would plug them in would it look like this: f(0.15)=0.225 cos (π/50(0.15))+0.32506/03/20
Luhan E.
I want to only use the cos equation, since as you said it would be easier06/03/20
Luhan E.
It should include 4 or more answers06/03/20
Luhan E.
Will it be okay if you can show me how to do the solution again only using the cos equation (it should include 4 or more answers)06/03/20
Luhan E.
thanks06/03/20
Luhan E.
so if it was above 0.15 m how would I know which x leads to this height06/02/20