Gradient on a hill
For f(x,y)=x^2+2y^2, grad f=<2x,4y>. At (1,-1), grad f=<2,-4>.
- The gradient points toward steepest increase; its magnitude is sqrt(20).
- Trace the worked reasoning before selecting the conclusion.
partial derivatives, gradients, multiple integrals, and optimization
For f(x,y)=x^2+2y^2, grad f=<2x,4y>. At (1,-1), grad f=<2,-4>.
Pause. Find what matters. Then make your move.