Find the Riemann sum for f(x) = sinx over the interval [0, 2pi], where x0 = 0, x1 = π/4, x2 = π/3, x3 = π, x4 = 2π, and c1 = π/6, c2 = π/3, c3 = 2π/3, c4 = 3π/2 Use a calculator to find the value accurate to 3 decimal places. Approximately 0.708 Approximately - 10.708 Approximately -0.708 None of these.