Question

What is the rate of change of f(x,y)=3xy+y^2 at the point (3,4) in the direction vector V =−3i−3j?
DV f=

Answer 1

@Algebraic!

Answer 2

dot the gradient with the unit vector: V/|V|

Answer 3

ah, thanks.

Answer 4

<12,17> dot <-3/sqrt(18),-3sqrt(18)> = -36/sqrt(18) - 51/sqrt(18)

Answer 5

thanks dude.

Answer 6

yep.