{VERSION 4 0 "IBM INTEL NT" "4.0" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 1 }{CSTYLE "2D Math" -1 2 "Times" 0 1 0 0 0 0 0 0 2 0 0 0 0 0 0 1 }{CSTYLE "2D Comment" 2 18 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 } {CSTYLE "2D Output" 2 20 "" 0 1 0 0 255 1 0 0 0 0 0 0 0 0 0 1 } {CSTYLE "word" -1 256 "" 0 0 128 0 0 1 0 0 0 0 0 0 0 0 0 1 }{PSTYLE "N ormal" -1 0 1 {CSTYLE "" -1 -1 "Times" 1 12 0 0 0 1 2 2 2 2 2 2 1 1 1 1 }1 1 0 0 0 0 1 0 1 0 2 2 0 1 }{PSTYLE "Heading 3" -1 5 1 {CSTYLE "" -1 -1 "Times" 1 12 0 0 0 1 1 1 2 2 2 2 1 1 1 1 }1 1 0 0 0 0 1 0 1 0 2 2 0 1 }{PSTYLE "Maple Output" -1 11 1 {CSTYLE "" -1 -1 "Times" 1 12 0 0 0 1 2 2 2 2 2 2 1 1 1 1 }3 3 0 0 0 0 1 0 1 0 2 2 0 1 }{PSTYLE "Title " -1 18 1 {CSTYLE "" -1 -1 "Times" 1 18 0 0 0 1 2 1 1 2 2 2 1 1 1 1 } 3 1 0 0 12 12 1 0 1 0 2 2 19 1 }{PSTYLE "Definition" -1 256 1 {CSTYLE "" -1 -1 "Times" 1 12 0 64 128 1 2 2 2 2 2 2 1 1 1 1 }1 1 0 0 0 0 1 0 1 0 2 2 0 1 }{PSTYLE "Problem" -1 257 1 {CSTYLE "" -1 -1 "Times" 1 12 0 0 255 1 2 2 2 2 2 2 1 1 1 1 }1 1 0 0 4 4 3 4 1 0 2 2 0 1 }{PSTYLE "N ormal" -1 258 1 {CSTYLE "" -1 -1 "Times" 1 12 0 0 0 1 2 2 2 2 2 2 1 1 1 1 }3 1 0 0 0 0 1 0 1 0 2 2 0 1 }{PSTYLE "Heading 2" -1 259 1 {CSTYLE "" -1 -1 "Times" 1 14 0 0 0 1 2 1 2 2 2 2 1 1 1 1 }3 1 0 0 8 2 1 0 1 0 2 2 0 1 }{PSTYLE "Definition" -1 260 1 {CSTYLE "" -1 -1 "" 0 0 0 64 128 1 0 0 0 0 0 0 0 0 0 1 }0 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 } {PSTYLE "Problem" -1 261 1 {CSTYLE "" -1 -1 "" 0 0 0 0 255 1 0 0 0 0 0 0 0 0 0 1 }0 0 0 -1 4 4 3 4 0 0 0 0 -1 0 }{PSTYLE "" 0 262 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 }3 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }{PSTYLE "" 0 263 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 }3 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }} {SECT 0 {EXCHG {PARA 18 "" 0 "" {TEXT -1 11 "Calculus II" }}{PARA 259 "" 0 "" {TEXT -1 32 "Lesson 17: Convergence of Series" }}}{EXCHG {PARA 260 "" 0 "" {TEXT -1 14 "Definition: A " }{TEXT 256 6 "series" } {TEXT -1 1 " " }{XPPEDIT 18 0 "Sum(a[n],n=1..infinity" "6#-%$SumG6$&% \"aG6#%\"nG/F);\"\"\"%)infinityG" }{TEXT -1 41 " consists of two seque nces: The sequence " }{XPPEDIT 18 0 "a[n]" "6#&%\"aG6#%\"nG" }{TEXT -1 41 " of terms of the series and the sequence " }{XPPEDIT 18 0 "S[n] =Sum(a[i],i=1..n" "6#/&%\"SG6#%\"nG-%$SumG6$&%\"aG6#%\"iG/F.;\"\"\"F' " }{TEXT -1 142 " of partial sums of the series. If the sequence of pa rtial sums converges to a limit L, then the series is said to converge to L and we write " }{XPPEDIT 18 0 "Sum(a[n],n=1..infinity)=L" "6#/-% $SumG6$&%\"aG6#%\"nG/F*;\"\"\"%)infinityG%\"LG" }{TEXT -1 1 "." }} {PARA 0 "" 0 "" {TEXT -1 168 "Suppose you have established somehow, ei ther directly or by some test, that a series converges to a number L. \+ How do we calculate this number to any specified accuracy?" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 83 "Not surprizingly, Maple can sum a lot of series already. For example, the sum of a " } {TEXT 256 16 "geometric series" }{TEXT -1 30 " is easy for Maple to co mpute." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 8 "restart;" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 50 "Sum(a*r^n,n=0..infinity)=sum (a*r^n,n=0..infinity);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#/-%$SumG6$*& %\"aG\"\"\")%\"rG%\"nGF)/F,;\"\"!%)infinityG,$*&F(F),&F+F)!\"\"F)F4F4 " }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 64 "Maple also knows that the har monic series diverges to infinity. " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 23 "sum(1/n,n=1..infinity);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#%)infinityG" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 107 "It also kno ws how to compute the sums of the various convergent p-series. For exa mple, the 3-series sums to" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 50 "Sum(1/n^3,n=1..infinity)=sum(1/n^3,n=1..infinity);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#/-%$SumG6$*&\"\"\"F(*$)%\"nG\"\"$F(!\"\"/F+;F(%)in finityG-%%ZetaG6#F," }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 4 "The " } {TEXT 256 21 "Riemann Zeta function" }{TEXT -1 58 " is defined for all p > 1 to give the sum of the p-series." }}{PARA 0 "" 0 "" {TEXT -1 43 "So, for example, the sum of the 3 series is" }}}{EXCHG {PARA 0 "> \+ " 0 "" {MPLTEXT 1 0 17 "Zeta(3)=Zeta(3.);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#/-%%ZetaG6#\"\"$$\"+.p0-7!\"*" }}}{EXCHG {PARA 0 "" 0 " " {TEXT -1 111 "If the series converges fast enough you can look at th e sequence of partial sums and get the desired accuracy. " }}{PARA 0 " " 0 "" {TEXT -1 52 "Lets see how fast the 3-series converges to Zeta(3 )." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 77 "for n from 10 by 100 \+ to 300 do Sum(1/i^3,i=1..n)=evalf(sum(1/i^3,i=1..n)) od;" }}{PARA 11 " " 1 "" {XPPMATH 20 "6#/-%$SumG6$*&\"\"\"F(*$)%\"iG\"\"$F(!\"\"/F+;F(\" #5$\"+')>`(>\"!\"*" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#/-%$SumG6$*&\"\" \"F(*$)%\"iG\"\"$F(!\"\"/F+;F(\"$5\"$\"+bf,-7!\"*" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#/-%$SumG6$*&\"\"\"F(*$)%\"iG\"\"$F(!\"\"/F+;F(\"$5#$\"+ >c/-7!\"*" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 74 "Well, the sum of the first 100 terms is accurate to 4 significant figures." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 165 "You can't decide fo r sure by looking at first few partial sums of a series that the serie s converges. For example, look at a few partial sums of the harmonic s eries." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 47 "seq(evalf(sum(1/i ,i=1..100*n)),n=1..5); n:='n':" }}{PARA 11 "" 1 "" {XPPMATH 20 "6'$\"+ =vP(=&!\"*$\"+[4.yeF%$\"+!)Qm#G'F%$\"+\"pH*plF%$\"+IM#Gz'F%" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 90 "Hmmm. You can't really tell by loo king at these that the harmonic series doesn't converge." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{SECT 0 {PARA 5 "" 0 "" {TEXT -1 8 "Problems" }}{PARA 5 "" 0 "" {TEXT -1 0 "" }}{EXCHG {PARA 261 "" 0 "" {TEXT -1 321 "Exercises: In each of the problems below, determine whether the series converges or diverges. Give a reason in each case. For the convergent series, get an estimate correct to 2 decimal place s of the sum of the series using psums or some other word of your own \+ devising. You can check with sum to see if Maple can sum it." }}} {EXCHG {PARA 0 "" 0 "" {XPPEDIT 18 0 "Sum( 1/(3+2*n)^2,n=1..infinity); " "6#-%$SumG6$*&\"\"\"F'*$,&\"\"$F'*&\"\"#F'%\"nGF'F'F,!\"\"/F-;F'%)i nfinityG" }{TEXT -1 1 " " }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 54 "This \+ series converges by comparison with the p-series " }{XPPEDIT 18 0 "Sum (1/n^2,n=1..infinity)" "6#-%$SumG6$*&\"\"\"F'*$%\"nG\"\"#!\"\"/F);F'%) infinityG" }{TEXT -1 39 ". Each partial sum is bounded above by " } {XPPEDIT 18 0 "Zeta(2)" "6#-%%ZetaG6#\"\"#" }{TEXT -1 148 " and the pa rtial sums form an increasing sequence, so we know the sequence of par tial sums converge. Checking to see what is programmed into Maple, " } }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 70 "sum(1/(3+2*n)^2,n=1..infin ity)=\nevalf(sum(1/(3+2*n)^2,n=1..infinity));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#/,&#!#5\"\"*\"\"\"*$)%#PiG\"\"#F(#F(\"\")$\"*S%*eA\"!\" *" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 47 "we get an exact sum. Check a few partial sums ." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 56 "seq( evalf(sum(1/(3+2*i)^2,i=1..100*n)),\nn=1..5); n:='n':" }}{PARA 11 "" 1 "" {XPPMATH 20 "6'$\"+$y%Q,7!#5$\"+y\"=N@\"F%$\"+_ih<7F%$\"+)[v'>7F% $\"+7V\"4A\"F%" }}}{EXCHG {PARA 0 "" 0 "" {XPPEDIT 18 0 "Sum(1/(n*(ln \+ (n))^2 ),n=2..infinity);" "6#-%$SumG6$*&\"\"\"F'*&%\"nGF'*$-%#lnG6#F) \"\"#F'!\"\"/F);F.%)infinityG" }{TEXT -1 1 " " }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 13 "The function " }{XPPEDIT 18 0 "1/(n*ln(n)^2)" "6#*&\" \"\"F$*&%\"nGF$*$-%#lnG6#F&\"\"#F$!\"\"" }{TEXT -1 94 " is a decreasin g for n > 1 (Take the derivative), so we can use the integral test on \+ this one." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 37 "int(1/(n*(ln ( n))^2),n=1..infinity); " }}{PARA 11 "" 1 "" {XPPMATH 20 "6#%)infinityG " }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 50 "Since the integral diverges, \+ the series diverges. " }}}{EXCHG {PARA 0 "" 0 "" {XPPEDIT 18 0 "Sum(1/ (2*n+1)^(1/3),n=0..infinity);" "6#-%$SumG6$*&\"\"\"F'),&*&\"\"#F'%\"nG F'F'F'F'*&F'F'\"\"$!\"\"F//F,;\"\"!%)infinityG" }{TEXT -1 56 " This se ries diverges, since it is a p-series with p < 1" }}}{EXCHG {PARA 262 "" 0 "" {XPPEDIT 18 0 "Sum((1+2^n)/(1+3^n),n=0..infinity);" "6#-%$SumG 6$*&,&\"\"\"F()\"\"#%\"nGF(F(,&F(F()\"\"$F+F(!\"\"/F+;\"\"!%)infinityG " }{TEXT -1 1 " " }}}{EXCHG {PARA 0 "" 0 "" {XPPEDIT 18 0 "Sum(( n^5+4 *n^3+1)/(2*n^9+n^4+2 ),n=0..infinity);" "6#-%$SumG6$*&,(*$%\"nG\"\"&\" \"\"*&\"\"%F+*$F)\"\"$F+F+F+F+F+,(*&\"\"#F+*$F)\"\"*F+F+*$F)F-F+F2F+! \"\"/F);\"\"!%)infinityG" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 41 "This \+ series converges by comparison with " }{XPPEDIT 18 0 "Sum(n^6/n^9" "6# -%$SumG6#*&%\"nG\"\"'*$F'\"\"*!\"\"" }{TEXT -1 2 ". " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 58 "evalf(int(( n^5+4*n^3+1)/\n (2*n^9+n^4+2 \+ ),n=1..infinity));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#$\"+6^g4V!#5" }} }{EXCHG {PARA 0 "" 0 "" {XPPEDIT 18 0 "Sum(sin (1/n^4 ),n=1..infinity) ;" "6#-%$SumG6$-%$sinG6#*&\"\"\"F**$%\"nG\"\"%!\"\"/F,;F*%)infinityG" }{TEXT -1 55 " This series converges by comparison with the 4-series. " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 39 "evalf(sum(sin(1/(n^4)), n=1..infinity));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#$\"+?@`P#*!#5" }}} {EXCHG {PARA 263 "" 0 "" {XPPEDIT 18 0 "Sum( n*e^(-n^2),n=1..infinity) ; " "6#-%$SumG6$*&%\"nG\"\"\")%\"eG,$*$F'\"\"#!\"\"F(/F';F(%)infinityG " }}}}}{MARK "17" 0 }{VIEWOPTS 1 1 0 1 1 1803 1 1 1 1 }{PAGENUMBERS 0 1 2 33 1 1 }