Question: Consider the function, f, of two variables defined by f(x,y) = (x^2 - 9)*sin(y). Find all the stationary points of f and classify each of them as either a local maximum, local minimum or a saddle point.
How would I answer this question?
Question: Consider the function, f, of two variables defined by f(x,y) = (x^2 - 9)*sin(y). Find all the stationary points of f and classify each of them as either a local maximum, local minimum or a saddle point.
How would I answer this question?
At the stationary points $\displaystyle f_x=f_y=0$.
To classify them you need to consider $\displaystyle f_{xx}, f_{xy} \text{ and } f_{yy}$.
This is all in your notes presumably and it's quite routine.
There are some good videos out there and of course there's Wikipedia.