{VERSION 3 0 "SUN SPARC SOLARIS" "3.0" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 }{CSTYLE "2D Math" -1 2 "Times" 0 1 0 0 0 0 0 0 2 0 0 0 0 0 0 }{CSTYLE "2D Comment" 2 18 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 } {CSTYLE "" -1 256 "" 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 257 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 272 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 273 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 } {CSTYLE "" -1 274 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 275 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 276 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 277 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 } {CSTYLE "" -1 278 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 279 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 280 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 283 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 } {PSTYLE "Normal" -1 0 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 }0 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }{PSTYLE "" 0 256 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 }3 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }} {SECT 0 {EXCHG {PARA 256 "" 0 "" {TEXT -1 15 "Maple Project 9" }} {PARA 0 "" 0 "" {TEXT -1 144 "Today we look at sequences and series. \+ A sequence is just a list of numbers; as such we can just define them \+ as functions on Maple. To define " }{XPPEDIT 18 0 "a[n];" "6#&%\"aG6# %\"nG" }{TEXT -1 4 " = " }{XPPEDIT 18 0 "2*n^2/(n^2+1);" "6#*(\"\"#\" \"\"*$)%\"nG\"\"#F%F%,&*$)%\"nG\"\"#\"\"\"F/\"\"\"F/!\"\"" }{TEXT -1 36 " , we use typical function notation:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 20 "a:=n->2*n^2/(n^2+1);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 104 "Maple can list elements of the sequence. For example, t o list out the tenth thru twentieth terms, type:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 19 "seq(a(n),n=10..20);" }}}{EXCHG {PARA 0 "" 0 " " {TEXT -1 77 "We can plot the sequence. To plot the first 100 terms \+ of the above sequence:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 62 "p lot( [ seq([n,a(n)],n=1..100) ] , style=point, symbol=cross);" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 148 "(Other symbol options are diamond , box, circle, and point.) The above sequence appears to have a limit , namely 2. We evaluate it in the usual way." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 23 "limit(a(n),n=infinity);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 79 "We can also implement sums and series using the \"sum \" command. Using the same " }{XPPEDIT 18 0 "a[n];" "6#&%\"aG6#%\"nG " }{TEXT -1 25 " as above, let's find " }{XPPEDIT 18 0 "sum(a[n],n \+ = 1 .. 200);" "6#-%$sumG6$&%\"aG6#%\"nG/%\"nG;\"\"\"\"$+#" }{TEXT -1 3 " ." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 19 "Sum(a(n),n=1..200 );" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 9 "value(%);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 9 "evalf(%);" }}}{EXCHG {PARA 0 "" 0 " " {TEXT -1 57 "Again, we don't have to use a capital \"s\" in our comm and." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 18 "sum(ln(n),n=4..7); " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 9 "evalf(%);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 234 "We can sum infinite series. If Maple re turns the infinity symbol, then the series diverges. You may recogniz e the first series as a simple geometric series. The second series di verges because, as we saw, the terms don't go to zero." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 29 "sum(1/3^(n-1),n=1..infinity);" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 24 "Sum(a(n),n=1..infinity);" }} }{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 9 "value(%);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 49 "I bet you're stoked now. Let's do some problem s." }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 7 "1) a) " }{TEXT 273 37 "Plot a hundred terms of the sequence " }{TEXT -1 1 " " }{XPPEDIT 18 0 "a[n ];" "6#&%\"aG6#%\"nG" }{TEXT -1 3 " = " }{XPPEDIT 18 0 "(-1)^n;" "6#), $\"\"\"!\"\"%\"nG" }{TEXT -1 6 " sin( " }{XPPEDIT 18 0 "1/n;" "6#*&\" \"\"\"\"\"%\"nG!\"\"" }{TEXT -1 4 " ) " }{TEXT 274 42 "and guess its \+ limit by looking at the plot" }{TEXT -1 64 ". (It almost looks like w e have 2 sequences in our plot. The " }{XPPEDIT 18 0 "(-1)^n" "6#),$ \"\"\"!\"\"%\"nG" }{TEXT -1 113 " term makes the terms oscillate betw een positive and negative values, i.e. values above and below the x-ax is.) " }{TEXT 272 38 "Then evaluate the limit using Maple. " }} {PARA 0 "" 0 "" {TEXT -1 29 " b) Consider the series " }{XPPEDIT 18 0 "sum(1/(n^2),n = 1 .. infinity);" "6#-%$sumG6$*&\"\"\"\"\"\"*$)% \"nG\"\"#F(!\"\"/%\"nG;\"\"\"%)infinityG" }{TEXT -1 4 " . " }{TEXT 275 232 " Plot the sequence of terms and the sequence of partial sums \+ on the same graph. (Plot 50 of each; use the display command for this , and also use different 'symbol' values in your plot commands so you \+ can see which plots are which.)" }{TEXT -1 2 " " }{TEXT 276 4 "Then" }{TEXT -1 1 " " }{TEXT 277 29 "evaluate the sum using Maple." }{TEXT -1 153 " Since the series converges, the terms must go to zero, and t hat's what we saw in the plot. (The value of this series is a famous \+ result due to Euler.)" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 52 "2) Remember the harmonic series is given by the sum " }{XPPEDIT 18 0 "sum(1/n,n = 1 .. infinity);" "6#-%$sumG6$*&\"\"\"\"\" \"%\"nG!\"\"/%\"nG;\"\"\"%)infinityG" }{TEXT -1 338 " . We know it d iverges (it gets infinitely large), but there is simply no way to see \+ this by just adding terms and seeing if the sequence of partial sums b lows up or not. To see what I mean, suppose we started with the first term of the harmonic series the day the universe was formed, 13 billi on years ago, and added a new term every " }{TEXT 256 6 "second" } {TEXT -1 3 ". " }{TEXT 257 72 "About how large would the partial sum \+ be today, assuming a 365-day year?" }{TEXT -1 124 " (Note: when you d o this on Maple, it may give you a kooky-looking answer. If it does, \+ just use \"evalf\" to get a decimal.)" }}{PARA 0 "" 0 "" {TEXT -1 0 " " }}{PARA 0 "" 0 "" {TEXT -1 88 "3) Remember the statement of the inte gral test: if f(x) is positive and decreasing, and " }{XPPEDIT 18 0 "a [n];" "6#&%\"aG6#%\"nG" }{TEXT -1 15 " = f(n), then " }{XPPEDIT 18 0 "sum(a[n],n = 1 .. infinity);" "6#-%$sumG6$&%\"aG6#%\"nG/%\"nG;\"\"\"% )infinityG" }{TEXT -1 29 " converges if and only if " }{XPPEDIT 18 0 "int(f(x),x = 1 .. infinity);" "6#-%$intG6$-%\"fG6#%\"xG/%\"xG;\"\" \"%)infinityG" }{TEXT -1 130 " converges (i.e. if the integral conve rges, so does the sum. If the integral diverges, so does the sum.) C onsider the series " }{XPPEDIT 18 0 "sum(n*exp(-n),n = 1 .. infinity) ;" "6#-%$sumG6$*&%\"nG\"\"\"-%$expG6#,$F'!\"\"F(/%\"nG;\"\"\"%)infinit yG" }{TEXT -1 5 " . " }{TEXT 279 16 "First check that" }{TEXT -1 1 " " }{TEXT 280 112 "the terms of this series do in fact decrease by tak ing a derivative; what is the interval on which it decreases?" }{TEXT -1 2 " " }{TEXT 283 69 "Then use the integral test to determine if it converges or diverges. " }{TEXT -1 121 " But note that this test does NOT give you the actual sum of the series; it only tells you if it co nverges or diverges. " }{TEXT 278 138 "To see this, sum the series. \+ Use the \"evalf\" command to doublecheck that the sum of the series is not equal to the value of the integral." }{TEXT -1 0 "" }}}}{MARK "20 3 2" 53 }{VIEWOPTS 1 1 0 1 1 1803 }