Question

Find the maximum rate of change of f(x,y) = x2y +2y

Answer 1

Answer:

Maximum rate of change at the point (-1,2) = √17

Direction is the direction of the gradient

Step-by-step explanation:

The gradient of a function (scalar or vectorial ) is a vector in the direction of maximum rate of change then

f( x,y ) =  x*2y  + 2y

grad    =  δ/δx i +  δ/δy j + δ/δz k

grad f(x,y)  = [ δ/δx i , δ/δy]  =  [ 2y , x+2 ]

at the point  ( -1 , 2 )

grad f(x,y)  = [4 , 1]

| grad f(x,y) |  =  √ (4)²  + (1)²   =  √17