Chop the interval into strips, put a rectangle on each one, and add them up. Where the top of the rectangle touches the curve is what separates the left, right and midpoint rules, and the trapezoidal rule slants the top instead.
Estimate the area under y=x2 from x=0 to x=4 using 4 strips and left endpoints.
Each strip is 1 wide, and the left edges are at 0, 1, 2 and 3.
The heights there are 0, 1, 4 and 9.
So the estimate is 0 plus 1 plus 4 plus 9, which is 14.
The answer is 14.
Where students go wrong
Using one endpoint too many, or one too few. Four strips have four left edges and four right edges, but five edges in total, so the left sum skips the last one and the right sum skips the first.
Also called left Riemann sum, right Riemann sum, midpoint rule, trapezoidal rule or approximating area under a curve.
What you can put on this worksheet
Left endpoints
Estimate the area under y=3x+3 from x=0 to x=4 using 4 strips and left endpoints.→ 30
Right endpoints
Estimate the area under y=3x+3 from x=0 to x=4 using 4 strips and right endpoints.→ 42
Midpoints
Estimate the area under y=3x+3 from x=0 to x=4 using 4 strips and midpoints.→ 36
The trapezoidal rule
Estimate the area under y=3x+3 from x=0 to x=4 using 4 strips and the trapezoidal rule.→ 36
Questions about these worksheets
Yes. Every riemann sums sheet is free to print and free to download as a PDF. There is no account to make, no email to hand over and no limit on how many you take.
Yes. The answer key prints on a second page, and you can choose whether it shows each question beside its answer or just the answers in a list.
Yes. Print straight from the page, or download the PDF and print that. The sheet is laid out for paper rather than squeezed off a screen, so there is room to work under each question, and the answer key comes out on its own page.
Calculus is usually taken around 12th grade or a first college course, though schools vary and plenty of students meet it earlier or later. Pick the difficulty rather than the grade: the easy level suits a first lesson on it, the hard level suits review before a test.
Yes, as many as you like. The questions are built fresh each time rather than picked from a fixed set of files, so pressing Generate gives a new sheet. That is what you want for a second class, a retake, or two students sitting next to each other.
That is the closest comparison, and Kuta Software is good software. It is also paid software you install on a computer. These worksheets run in a browser tab for free, with no account and nothing to install. Like Kuta, the riemann sums questions are generated when you ask for them rather than pulled from a fixed set of files, so two classes never get the same sheet, and the answer key comes with it.
Yes. There are three levels, and you can tick more than one for a sheet that mixes them, in which case the questions come out easiest first. The harder levels are not just larger numbers: they ask for something the easy ones do not.
You pick from 4: left endpoints, right endpoints, midpoints and the trapezoidal rule. Tick as many as you want and set how many of each, or let it spread them evenly.
Using one endpoint too many, or one too few. Four strips have four left edges and four right edges, but five edges in total, so the left sum skips the last one and the right sum skips the first.