A plane wave is described by the equation `y = 3 cos(x/7 -10r -pi/6)` . The maximum velocity of the particles of the medium due to this wave is
30
3/4
`(3pi)//2`
40
but how the max. velocity is 30? according to me for maximum value the value of cos(x/7-10r-pi/6) should be 1,hence the max. velocity should be 3.