Applied Maths particle projection.

If the particle returns to
the plane, find:
(i) the time of flight;
(ii) the time taken to reach the highest point.
Hint: You may use the formulas for the horizontal x(t) and vertical y(t) displacement
of the particle:
x(t) = u cos(α)t, y(t) = u sin(α)t −
1
2
gt2
, g = 10m/sec2
,
where u is the initial speed and α is the initial inclination angle to the horizontal