3. The temperature of points in space given by a scalar field is T(x, y, z) = x + y - - N a. Find the temperature, T, at the point (-1, 0, 5). b. Evaluate the directional derivative of the scalar function T(x, y, z) at the point (1, 3,-1) in the direction of (2, 1,2). c. An isothermal is a surface upon which the temperature of the surface is constant i. find the equation of the isothermal (i.e. the surface) through the point (1,1,2) by making z the subject ii. in Matlab plot the equation of the isothermal contours in the x - y plane s.t. -5 x 5 and -5 y 5 (include screenshot) d. A mosquito is located at the point (1,1,2), and desires to fly in such a direction that it will get cool as soon as possible. In what direction should it move and why?