If a = amplitude ; y = displacement; w = angular frequency
V = Velocity, then
V2 = w2 (a2 – y2)
For first case. u12 = w2(a2 – x12) →1)
( ∵velocity = u1 Displacement = x1)
For second case, u22 = w2 (a2 – x22) →2)
(velocity = u2 Displacement = x2)
Subtracting equation 2) from equation 1);