Second partial derivative test example, part 1

[@saulflores5052]

OMG is this Grant Sanderson from 3Blue1Brown??? The voice caught me off guard. BTW, Great video! A++

[@Riccardopapale]

you are really good at explaining

[@cherrytree5026]

amazing video man thank you

[@АнастасияКараван-л1н]

why isn't (0,1) a critical point as well? It's the point we found first and then plugged into the second equation.

[@johnc.5600]

my question as well??

[@Sharpshark136]

Because (0,1) works only for the first equation. That's why you plug the values 0 and 1 separately to the second one. If you plug them simultaneously you will obtain a contradiction.

[@hungpham2803]

@@Sharpshark136 Because it's x=0 OR y=1. They're not the coordinates of a critical point. They're actually the possibilities we were analyzing further in the video (from 3:10).

[@bowlofsoba]

At 6:00, "critical points, which means all partial derivatives equal to zero."

[@danielmaxwell7536]

Thats because both the partial derivatives need to be zero and in order for this to be satisfied x=0 and y=1 is not applicable(not a critical point)