Use the contour diagram for $f(x,y)$ shown below to estimate the directional derivative of $f$ in the direction $\vec{v}$ at the point P. (a) At the point $P = (2,2)$ in the direction $\vec{v} = \vec{i}$, the directional derivative is approximately (b) At the point $P = (3,2)$ in the direction $\vec{v} = -\vec{i}$, the directional derivative is approximately (c) At the point $P = (4,1)$ in the direction $\vec{v} = (\vec{i} + \vec{j})/\sqrt{2}$, the directional derivative is approximately (d) At the point $P = (3,0)$ in the direction $\vec{v} = -\vec{i}$, the directional derivative is approximately

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You can earn partial credit on this problem.