(Solved): please solve all  1) For the given function and vector, \( \vec{v} \), find the directional der ...

1) For the given function and vector, \( \vec{v} \), find the directional derivative. \[ f(x, y)=y x^{2}-3 x+y^{2}, P(1,1), \vec{v}=\langle 1,2\rangle \] 2) Find the directional derivative of the function in the direction of the unit vector \[ \begin{array}{c} \vec{u}=\langle\cos \theta, \sin \theta\rangle \\ f(x, y)=x^{2}-3 y^{2}, \quad \theta=\pi / 3 \end{array} \] 3) Find the gradient of \( f(x, y)=\frac{25-x^{2}+y^{2}}{4} \), then find the gradient at the point \( \mathrm{P}(2,1) \)