Here's the question you clicked on:
elica85
use the second derivative test to find local extrema and saddle point of f(x,y)=6x^2-2x^3+3y^2+6xy
df/dx=12x-6x^2+6y df/dy=6y+6x next step is to find critical points
set df/dy=0 and y=-x i'm stuck on df/dx=0...
don't you need second derivative?
o wait, nevermind i use y=-x in setting df/dx=0 i think i can get it now (slapping forehead)