Area with sums problem: Find the upper and lower sums of f(x) = -2x + 4 on the interval [0, 2] using four subintervals of equal length.
'Note: do not use the summation formulas; calculate the area of the rectangles directly.'

Question

Area with sums problem: Find the upper and lower sums of f(x) = -2x + 4 on the interval [0, 2] using four subintervals of equal length. 
'Note: do not use the summation formulas; calculate the area of the rectangles directly.'

anonymous · Answer

ok so if i can't use summation formulas, how should i go about this? 
i'll get to work drawing a graph

anonymous · Answer

|dw:1387422130586:dw|
something like this?
width for each should be 0.5   (b-a/n= 2-0/4= 0.5)