- #1
slain4ever
- 63
- 0
Homework Statement
1. for the surface z=9 - x^2 - y^2 find,
i) the gradient at (1,1,7) in the direction making an angle alpha with the x-axis
ii) the max gradient at the point (1,1,7) and the value of alpha for which it occurs
2. find the stationary point of z=x^2 +2x +3y^2 -3xy + 5 and determine the nature of this point
Homework Equations
this is what i need, I am not sure of the equation you use to differentiate an equation like this.
The Attempt at a Solution
I know you have to partially diff it with respect to x and then with respect to y,
but I don't know how to combine the 2 together so you can just put the numbers in and find the gradient.