3. A particular scalar field α is given by a. α=10e−ˣ sin(πy/3) in Cartesian b. α=5rhosin(Φ) in cylindrical c. α=20cos(Θ)/r² in spherical find its gradient at P(0,−1,3) for Cartesian, P(2,π/2,7) for cylindrical and P(5,30⁰,60⁰) for spherical coordinate systems.