Graph each function (x) over the given interval. Partition the interval into four subintervals of equal length.

Graph each function ƒ(x) over the given interval. Partition the interval into four subintervals of equal length. Then add to your sketch the rectangles associated with the Riemann sum Σ⁴_{k =1}ƒ(c_k) Δx_k , given that ck is the 

(a) Left-hand endpoint, 

(b) Righthand endpoint, 

(c) Midpoint of the kth subinterval. 

ƒ(x) = sin x, [-π, π]