00:01
For this problem, we are given the function f of xyz equals xy plus yz plus x, the vector v equals 2i plus j minus k, and the point 1 -1 -1.
00:11
And we are asked to find the directional derivative of f in the direction of v at the point 1 -1 -1.
00:17
So to begin, we need to normalize our vector v to find a unit vector in the same direction.
00:25
So we'll have v divided by its magnitude, which is going to be the same.
00:30
Square root of 2 squared, so 4, plus 1, plus 1, or negative 1 squared, so plus 1.
00:37
So we can see then that our vector v is going to be 1, or our vector e, v, rather, is going to be 1 over root 6 times 2i plus j minus k.
00:54
Now with that, we next want to find the gradient, oops, i do not want ink to shape, we next want to find the gradient of our function at the point x, y, z...