please explain the calculations

Find the directional derivative, fv, of f(I, y) = VAr - 3y at the point (3, -2) in the direction v = i+j. 1. fv 2. fv 12 3. fv 4. fv 5. f.Suppose that over a certain region of space the electrical potential V is given by V(x. y. 2) = 7r - Ary + ryz. Find the rate of change of the potential at P(1. 3, 7) in the direction of the vector v=i-j -k. 23 1. V3 2. -23 23 3. V3If the graph of z = f(r, y) at P = (1, 2) has slope = -2 in the r-direction and slope -1 in the y-direction, find the slope at P in the direction of the vector v = 3i - 4j. 1. slope 2. slope 3. slope 5 4. slope 5. slopeIf f(z, y) = 1 + 4y. use the gradient vector Vf(5, 1) to find the tangent line to the level curve f(r, y) = 29 at the point (5, 1). 1. 2x + 8y = 29 2. 5x + 4y = 29 3. 101 - 8y = 29 4. 10r + 8y = 29 5. 5r - 4y = 29