{VERSION 3 0 "APPLE_68K_MAC" "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 Output" 2 20 "" 0 1 0 0 255 1 0 0 0 0 0 0 0 0 0 } {CSTYLE "" -1 256 "" 1 14 0 0 0 0 0 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 257 "" 1 14 0 0 0 0 0 0 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 "Maple Output" 0 11 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 }3 3 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }} {SECT 0 {EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }{TEXT 256 18 "Pg. 81, Pr oblem #2" }}{PARA 0 "" 0 "" {TEXT -1 123 " A solution of salt an d water flow at 6 liters per minute into a tank that initially held 50 lliter with 5 kilograms " }}{PARA 0 "" 0 "" {TEXT -1 117 " of s alt dissolved into it. The solution flows out of the tank at the same rate. If the concentration of the " }}{PARA 0 "" 0 "" {TEXT -1 167 " solution entering the tank is 0.5kg/L, find the mass of salt in the tank after t minutes. When will the concentration of salt in the tank reach 0.3kg/L." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 33 "solution rate into tank: 6 L/min " }}{PARA 0 "" 0 "" {TEXT -1 57 "concentration of solution entering ta nk: 0.5 kg of salt/L" }}{PARA 0 "" 0 "" {TEXT -1 24 "tank initially he ld 50 L" }}{PARA 0 "" 0 "" {TEXT -1 17 "rate out: 6 L/min" }}{PARA 0 " " 0 "" {TEXT -1 44 "Let x be amount of salt in tank, x(0) = 5 kg" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 14 "So , our de is:" }}{PARA 0 "" 0 "" {TEXT -1 95 " \+ dx/dt = 3 kg/min - (6 L/min) * (x(t) kg / 50L) ; x(0) = 5 kg " }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 34 "eq1:=diff(x(t),t)= (3 - .12*x(t));" }}{PARA 11 "" 1 " " {XPPMATH 20 "6#>%$eq1G/-%%diffG6$-%\"xG6#%\"tGF,,&\"\"$\"\"\"F)$!#7! \"#" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 32 "sol1:=dsolve(\{eq1,x (0)=5\},x(t));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%%sol1G/-%\"xG6#%\" tG,&$\"#D\"\"!\"\"\"-%$expG6#,$F)$!+++++7!#5$!#?F-" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 58 "Now, we know the mass of salt in the tank after t minutes." }}{PARA 0 "" 0 "" {TEXT -1 63 "The next question is when wi ll the concentration reach .3 kg/L." }}{PARA 0 "" 0 "" {TEXT -1 67 "Th is means the same thing as when does the tank have 15 kg of salt?" }} {PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 26 "solve(subs(x(t)=15,sol1));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#$ \"+0lAwd!\"*" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 53 "This is the same \+ answer we got when doing it by hand." }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 0 " " }}{PARA 0 "" 0 "" {TEXT -1 0 "" }{TEXT 257 10 "Pg. 82 #24" }}{PARA 0 "" 0 "" {TEXT -1 8 " " }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 138 " a. The half-life of carbon-14 is 5550 years. If only 2 percent of the original amount of carbon-14 remains, how long has it been the re?" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 71 "b. Redo the problem assuming 3 percent of the original amount \+ remains." }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 189 "c. Each of the figures in parts a and b represents a 1% \+ error in measuring the two parameters of half-life and percent of mass remaining. Which parameter is the model more sensitive to? " }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 191 "First we must solve our d.e. dp/d t = -kp, which is seperable. Our final equation for the rate of decay of carbon-14 is p = p(0) * exp(-kt). We also know that P(0) = 1 and \+ p(half life) = .5." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 34 "eqt1 := (diff(p(t),t) = -k*p(t)); " }{TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%%eqt1G/-%%diffG6$-%\"pG6#%\"tGF,,$*&%\"kG\"\"\"F)F0!\"\"" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 36 "solt1 := dsolve(\{eqt1,p(0)= 1\},p(t));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%&solt1G/-%\"pG6#%\"tG- %$expG6#,$*&%\"kG\"\"\"F)F0!\"\"" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 40 "k1:=solve(subs(\{p(t)=.5,t=5550\},solt1));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%#k1G$\"+RQ\"*[7!#8" }}}{EXCHG {PARA 0 "> \+ " 0 "" {MPLTEXT 1 0 38 "t1:=solve(subs(\{p(t)=.2,k=k1\},solt1));" }} {PARA 11 "" 1 "" {XPPMATH 20 "6#>%#t1G$\"+$4q')G\"!\"&" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 100 "This is the answer for Part A, We found \+ 12876 years but rounded k differently. Maple is more exact." }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "solt1;" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#/-%\"pG6#%\"tG-%$expG6#,$*&%\"kG\"\"\"F'F.!\"\"" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 40 "k2:=solve(subs(\{p(t)=.5,t=5 600\},solt1));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%#k2G$\"+AGwP7!#8" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 38 "t2:=solve(subs(\{p(t)=.3, k=k2\},solt1));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%#t2G$\"+Jt+F(*!\" '" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 111 "This is the answer to Part \+ B, we found 9709 years but again rounded k differently. Maple is agai n more exact.\n" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 129 "In Part C you must compare our values in Parts A and B to the answer to problem 23, this should be on the web by another group. " }}}}{MARK "22 0 0" 129 }{VIEWOPTS 1 1 0 1 1 1803 }