00:01
For this problem, we are asked to find a vector that gives the direction in which the function f of x, y equals each the power of 2x, sine y, increases most rapidly at the point 0 pi by 4, and to find the maximum rate.
00:14
Now, this is a sort of cheekily asked question.
00:19
The vector, which gives the direction in which the given function increases most rapidly, that is actually just asking for the gradient of the function at the point 0 pi by 4.
00:31
So our first step here is to find the gradient of our function at a point x y.
00:38
Partial derivative with respect to x will be 2 e to the power of 2x sine of y.
00:46
The partial derivative with respect to y will be e to the power of 2x cos of y.
00:55
Now evaluating the gradient at the point 0 pi by 4, we have that this will be 2 times e to the power of 0 or just 2 times.
01:07
Sign of pi by 4, which would be 1 over root 2...