Posted by Farah on .
An oceanographer measured a set of sea waves during a storm and modelled the vertical displacement of waves in meters using the equation h(t)=0.6cos2t+0.8sint, where t is the time in seconds.
a) Determine the vertical displacement of the wave when the velocity is 0.8m/s
b) Determine the maximum velocity of the wave and when it occurs.
c) When does the wave first change from a hill to a trough? Explain.
Ans: I tried finding the part a) by first finding the derivative, then how do i go about simplifying it. how do i find the max velocity with cos and sin in the function?

Math pplication of Sin and Cos&thier derivative 
bobpursley,
velocity is max when acceleration is zero, so find acceleration, set it to zero, and find t.