give that f(x,y) = 5-x^2 -2y^2 and (x', y') = (-1,-1), the direction of the max rate of increase is
c. (1/5)^(1/2) (1,2)
isit all or just one of the above?
i thought the answer should be a. but my notes stats that it is c.
may i also know what formula i should used to get the direction that is gving zero rate of increase?
this direction would be perpendicular to grad f(x',y') hence we are looking for the tangent vertor which is the directional derivative at (x', y'), and that is equal to 2(5)^(1/2)
however my answers showed that the answer is plus minus (1/5)^(1/) (2, -1)
may i know what is wrong with my understanding please?