The Cartesian coordinates of a point are given. (−9, 9) (i) Find polar coordinates (r, θ) of the point, where r > 0 and 0 ≤ θ < 2π. (r, θ) = (ii) Find polar coordinates (r, θ) of the point, where r < 0 and 0 ≤ θ < 2π. (r, θ) = What is the concentration of H+ ions at a pH = 2?
