Hi aspirant,

To find the directional derivative we need to use the concept of partial differentiation so f(x,y,z)= 2xyz i + xz² j . Now placing the given value of points we get, 4i + j. Now to find its value in in direction of a given vector we need to find its dot product with the same and divide it by its modulus.

i.e. 8-1/9=7/9.

Hope it helps!!