{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 } {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 2" }} {PARA 0 "" 0 "" {TEXT -1 209 "This lab we will fool around with expone ntials and logs. One thing to keep in mind: it might be a good idea t o save your worksheet from time to time, in case your computer locks u p or won't print or whatever." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }} {PARA 0 "" 0 "" {TEXT -1 95 "First let's introduce a few functions. H ere is how we write the exponential function in Maple:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 7 "exp(x);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 21 "Here is the number e:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 7 "exp(1);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 145 "Maple doesn't feel like giving us a decimal. Whenever we want to convert s ome numerical expression to a decimal, we can use the \"evalf\" comman d." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 14 "evalf(exp(1));" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 68 "If we want to see e evaluated to 2 0 decimal places, we simply write:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 17 "evalf(exp(1),20);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 69 "Let's just assign this value to the letter \"e\" so we can refe r to it." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 10 "e:=exp(1);" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 85 "The inverse of the exponential, th e natural logarithm, is written as we would expect:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "ln(x);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 68 "It's a good idea to remember these 2 simple values of the logar ithm:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "ln(1);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "ln(e);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 90 "So now let's try a few things. First, we can get Maple t o do limits. We can verify that " }{XPPEDIT 18 0 "limit((1+x)^(1/x),x = 0);" "6#-%&limitG6$),&\"\"\"\"\"\"%\"xGF)*&\"\"\"F)F*!\"\"/F*\"\"! " }{TEXT -1 16 " = e by typing:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 23 "limit((1+x)^(1/x),x=0);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 183 "The first thing in the parentheses is the function we wi sh to take the limit of; the next is the number we want to approach. \+ Simple, no? We can easily verify our homework problem: " }{XPPEDIT 18 0 "limit((exp(3*x)-exp(-3*x))/(exp(3*x)+exp(-3*x)),x = -infinity)" "6#-%&limitG6$*&,&-%$expG6#*&\"\"$\"\"\"%\"xGF-F--F)6#,$*&\"\"$F-F.F-! \"\"F4F-,&-F)6#*&\"\"$F-F.F-F--F)6#,$*&\"\"$F-F.F-F4F-F4/F.,$%)infinit yGF4" }{TEXT -1 73 " = -1. First we will use the \"limit\" command \+ with a capital \"L\"; this " }}{PARA 0 "" 0 "" {TEXT -1 196 "will spit the limit back out at us so we can verify if we typed in the correct \+ expression or not. Note how the parentheses are used in the command s o that fraction is in the form we want it. " }}}{EXCHG {PARA 0 "> \+ " 0 "" {MPLTEXT 1 0 61 "Limit((exp(3*x)-exp(-3*x))/(exp(3*x)+exp(-3*x) ),x=-infinity);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 9 "value(%); " }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 329 "We can see this, of course, \+ in the behavior of the graph. (Save yourself some time with this next command: highlight the \"Limit\" command above with your cursor and u se the \"Copy\" command in the file menu to copy it, then use the \"Pa ste\" command in the same menu to paste it where you want it, then jus t make some minor changes.)" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 58 "plot((exp(3*x)-exp(-3*x))/(exp(3*x)+exp(-3*x)),x=-20..20);" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 136 "From this plot we can also see th at the limit as x goes to infinity is 1 (which can also easily be chec ked with the \"limit\" command).. " }}{PARA 0 "" 0 "" {TEXT -1 0 "" } }{PARA 0 "" 0 "" {TEXT -1 183 "It is instructive to see what happens i f we don't put in the parentheses correctly in our limit command; the \+ whole thing will be screwed up. Watch out for that stuff! Whoooaaa!! !! " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 57 "Limit(exp(3*x)-exp( -3*x)/exp(3*x)+exp(-3*x),x=-infinity);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 194 "That certainly isn't what we wanted. Anyway, just remem ber: proper placement of parentheses is positively paramount to the pe rfection of your project. Next: we know Maple can take derivatives." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 19 "diff(x^3*exp(x),x);" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 16 "Another example:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 11 "f:=ln(x-3);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 10 "diff(f,x);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 180 "B ut what if I asked you what its 100th derivative was? What would you \+ do then, huh? You think you're so smart, eh? One way to do it is jus t use the \"$\" notation in our command. " }}}{EXCHG {PARA 0 "> " 0 " " {MPLTEXT 1 0 14 "diff(f,x$100);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 311 "That's the hundreth derivative. To get any other derivative, say the third derivative, you would just use \"x$3\" in the above command . THere is also another way to do this. First define ln(x-3) as a FU NCTION. (What we defined above as \"f\" is just an expression. A fun ction we can actually plop values into.)" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 14 "f:=x->ln(x-3);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 77 "Now we type the following expression, to get the derivative of thi s function:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 8 "D(f)(x);" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 25 "The second derivative is:" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 13 "(D@@2)(f)(x);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 24 "Its 100th derivative is:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "(D@@100)(f)(x);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 260 "The neat thing about this way of doing it is we \+ can just plop values right into the derivative if we want, which we co uld not do with the \"diff\" command. To EVALUATE the derivative at a particular value, say at x=2, instead of typing \"D(f)(x)\" we simply type:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 8 "D(f)(2);" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 39 "The same goes for any other deriva tive:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 13 "(D@@2)(f)(2);" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "(D@@100)(f)(2);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 84 "If you're not flabbergasted at the sheer \+ power of Maple, you should leave right now." }}{PARA 0 "" 0 "" {TEXT -1 81 "Start a new worksheet, put your name at the top. Do these prob lems, why dontcha." }}{PARA 0 "" 0 "" {TEXT -1 29 "1) The question is , what is " }{XPPEDIT 18 0 "limit(ln(ln(x))/ln(x),x = infinity);" "6#- %&limitG6$*&-%#lnG6#-F(6#%\"xG\"\"\"-%#lnG6#%\"xG!\"\"/%\"xG%)infinity G" }{TEXT -1 94 " ? If wer're lazy, we could just plot it and try to eyeball the limit. Plot the curve y = " }{XPPEDIT 18 0 "ln(ln(x))/l n(x);" "6#*&-%#lnG6#-F%6#%\"xG\"\"\"-%#lnG6#%\"xG!\"\"" }{TEXT -1 348 " on the interval [2,30]. What's your guess on what the limit might b e? Now plot it on [2,100]. What's your guess now? Plot it on [2,100 0]. How 'bout now? Now actually calculate the limit using Maple. Th e moral of the story is, you can't really tell what the function is do ing as x gets large by looking at small values of x; it can fool you. " }}{PARA 0 "" 0 "" {TEXT -1 586 "2) Find the equation of the tangent \+ line to the curve y = ln (2x+1) at x=20, and plot this curve and the l ine on the same graph over the interval [1,50]. DO EVERYTHING WITH MA PLE COMMANDS, AND MAPLE COMMANDS ONLY. (Hint: take this one step by s tep. First define ln(2x+1) as a function. Then think about what you \+ need to get the equation of a line. You need: 1) a slope, which can \+ be found by taking a derivative and plugging in your x-value, and 2) \+ your point, of which you already have the x-value, so just find the y- value. Then write your equation of a line and do the plot.)" }}}} {MARK "15 0 0" 1 }{VIEWOPTS 1 1 0 1 1 1803 }