ok do i draw this graph
Mr F says: Yes, use a graphics calculator.
and then add the rectangles,
Mr F says: Yes, add the area of each of the four rectangles. As has already been stated, the total area is $\displaystyle f(x_0) + f(x_1) + f(x_2) + f(x_3)$, where $\displaystyle x_0 = -1.5, ~x_1 = -0.5, ~x_2 = 0.5 \, $ and $\displaystyle \, x_3 = 1.5$.
if so can u tell me what it is supposed to look like,
Mr F says: Draw the graph (use a graphics calculator to get it) and draw in the rectangles. Then you'll know what it looks like.
im sorry i am completely lost, i don't understand anything!
Mr F says: But you must surely have some examples to follow ....?