$04//$ Let $fbea$ function of two variables that has continuous partial derivatives and consider the points $A\left(1,3\right),B\left(3,3\right)$ $C\left(l,$ $ca,7$ and $D\left(6,15\right).$ The directional derivative of j at $A$ in the direction of the vector $\vec{AB} $ is 3 and the directional derivative at $A$ in the direction of $\vec{AC} $ is $26$ Find the directional derivative of $y$ at $A$ in the direction of the vector $\vec{AD} $ $AD.$ $\left(S$ $narky\right)$ $y$

Use directional derivative definition to find derivative of $f\left(x,y\right)=x^{2}+y^{2}$ at the direction of $→=\dfrac {\sqrt{3} } {2}\vec{i} +\dfrac {1} {2}\vec{i} $ at the point $\left(1,2\right)$

The directional derivative of $b=xyz$ z at the point $\left(1,$ $1,$ $1\right)$ $1n$ $n$ the direction i $is^{.}$ $:$