When the terms come from a function that is positive, continuous and decreasing, the series and the integral of that function either both converge or both diverge. The same integral, started at N instead of 1, bounds the error left after N terms.
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Pick more than one for a sheet that mixes them.
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Use the integral test to decide whether each series converges, or bound the remainder as asked.
n=2∑∞n(lnn)21The series convergesf(x)=x(lnx)21 is positive, continuous and decreasing for x≥2∫2∞x(lnx)21dx=ln21
Bound the remainder R20for n=1∑∞6e−nR20≤e206
n=1∑∞6ne−n2The series convergesf(x)=6xe−x2 is positive, continuous and decreasing for x≥1∫1∞6xe−x2dx=e3
Bound the remainder R6for n=1∑∞n31R6≤721
n=1∑∞(n+5)23The series convergesf(x)=(x+5)23 is positive, continuous and decreasing for x≥1∫1∞(x+5)23dx=21
Bound the remainder R6for n=1∑∞5e−3nR6≤3e185
n=2∑∞nlnn6The series divergesf(x)=xlnx6 is positive, continuous and decreasing for x≥2∫2∞xlnx6dx=∞
Bound the remainder R4for n=1∑∞n42R4≤961
n=1∑∞n2+5nThe series divergesf(x)=x2+5x is positive, continuous and decreasing for x≥3(the terms before that do not affect convergence)∫1∞x2+5xdx=∞
Bound the remainder R5for n=1∑∞e−nR5≤e51
n=1∑∞nlnnThe series divergesf(x)=xlnx is positive, continuous and decreasing for x≥3(the terms before that do not affect convergence)∫1∞xlnxdx=∞
Bound the remainder R20for n=1∑∞n34R20≤2001
n=1∑∞n2+94nThe series divergesf(x)=x2+94x is positive, continuous and decreasing for x≥3(the terms before that do not affect convergence)∫1∞x2+94xdx=∞
Bound the remainder R4for n=1∑∞e−3nR4≤3e121
n=2∑∞nlnn3The series divergesf(x)=xlnx3 is positive, continuous and decreasing for x≥2∫2∞xlnx3dx=∞
Bound the remainder R4for n=1∑∞n41R4≤1921
n=1∑∞n21The series convergesf(x)=x21 is positive, continuous and decreasing for x≥1∫1∞x21dx=1
Bound the remainder R8for n=1∑∞3e−3nR8≤e241
n=2∑∞n(lnn)22The series convergesf(x)=x(lnx)22 is positive, continuous and decreasing for x≥2∫2∞x(lnx)22dx=ln22
f(x) = xe^(-x^2) is positive and continuous, and decreasing for x ≥ 1.
Substitute u = x^2: the integral from 1 to infinity is (1/2)e^(-1).
The integral is finite, so the series converges.
The answer is ∫1∞xe−x2dx=2e1; converges.
Where students go wrong
Giving the value of the integral as the sum of the series. The test only says whether the series converges; the integral and the sum are different numbers.
Also called integral test for convergence, Cauchy integral test or integral test remainder estimate.
What you can put on this worksheet
Evaluate the integral and decide
n=1∑∞n2+74n→ ∫1∞x2+74xdx=∞The series diverges
Bound the remainder with an integral
Bound the remainder R20for n=1∑∞n35→ R20≤1601
Questions about these worksheets
Yes. Every integral test 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 integral test 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 2: evaluate the integral and decide and bound the remainder with an integral. Tick as many as you want and set how many of each, or let it spread them evenly.
Giving the value of the integral as the sum of the series. The test only says whether the series converges; the integral and the sum are different numbers.