Math Help - find the derivative.......

1. find the derivative.......

find the derivative f(x , y , z) = x^3 - xy^2 -z at Po (1,1,0) in the direction of
→ → → →
a = 2i - 3j + 6k

2. Originally Posted by m777
find the derivative f(x , y , z) = x^3 - xy^2 -z at Po (1,1,0) in the derivative of
→ → → →
a = 2i - 3j + 6k
$\nabla f (x,y,z) = \left< f_x,f_y,f_z\right> = \left< 3x^2 - y^2, 2xy, -1 \right>$

i don't understand what you mean by "in the derivative of $a = 2 \bold{i} - 3 \bold{j} + 6 \bold{k}$"