Answer :
So the question if find y'' for 4y=cos2x
First, find y by dividing by 4. y = cos2x/4
Then, take the first derivative. y' = -sin2x/2
Then, take the second dervative. y'' = -cos2x
First, find y by dividing by 4. y = cos2x/4
Then, take the first derivative. y' = -sin2x/2
Then, take the second dervative. y'' = -cos2x