Compute the directional derivative of the functionf(x,y,z)=x?arctan(y+2zz)f(x,y,z)=x?arctan(y+2zz)at the point(x,y,z)=(1,?5,1)(x,y,z)=(1,-5,1)in the direction of the vectorv?=?1,0,?1?v?=?1,0,?1?.Dv?f(1,?5,1)=Dv?f(1,?5,1)=Give the value with two decimal places.

Compute the directional derivative of the function y + 2z f (x, y, z) = x arctan Z at the point (x, y, z) = (1, -5, 1) in the direction of the vector U = (1, 0, -1). D-f(1, -5, 1) = Number Give the value with two decimal places