{VERSION 5 0 "IBM INTEL NT" "5.0" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 1 }{CSTYLE "" -1 256 "" 0 1 0 128 0 1 0 0 0 0 0 0 0 0 0 0 } {CSTYLE "" -1 257 "" 0 1 0 128 0 1 0 0 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 258 "" 0 1 0 128 128 1 0 0 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 259 "" 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 260 "" 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 261 "" 0 1 128 0 0 1 0 1 0 0 0 0 0 0 0 0 } {CSTYLE "" -1 262 "" 0 1 128 0 0 1 0 1 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 263 "" 0 1 128 0 0 1 0 1 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 264 "" 0 1 128 0 0 1 0 1 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 265 "" 0 1 128 128 128 1 0 0 0 0 0 0 0 0 0 0 }{PSTYLE "Normal" -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 1" -1 3 1 {CSTYLE "" -1 -1 "Times" 1 18 0 0 0 1 2 1 2 2 2 2 1 1 1 1 }1 1 0 0 8 4 1 0 1 0 2 2 0 1 }{PSTYLE "Heading 2" -1 4 1 {CSTYLE "" -1 -1 "Times" 1 14 0 0 0 1 2 1 2 2 2 2 1 1 1 1 }1 1 0 0 8 2 1 0 1 0 2 2 0 1 }} {SECT 0 {PARA 0 "" 0 "" {TEXT -1 0 "" }{TEXT 257 49 "High School Modul es > Algebra by Gregory A. Moore" }}{PARA 3 "" 0 "" {TEXT -1 4 " " }{TEXT 256 26 "Imaginary &Complex Numbers" }}{PARA 0 "" 0 "" {TEXT -1 196 "\nAn exploration of the derivation of imaginary and complex numbe rs, numerical operations with imaginary and complex numbers, complex c onjugates, and graphing complex numbers on the complex plane.\n" }} {PARA 0 "" 0 "" {TEXT 258 153 "[Directions : Execute the Code Resource section first. Although there will be no output immediately, these de finitions are used later in this worksheet.]" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{SECT 0 {PARA 4 "" 0 "" {TEXT -1 8 " 0. Code" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 22 "restart; with(plots): " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 673 "ComplexPlot := proc( z )\nlocal \+ a,b,c,d,Axes,Pt, Run, Rise;\nif (Re(z) = 0) then b := 1; else b := 1. 3*abs(Re(z)); fi; \na := - b;\nif (Re(z) > 0) then a := a/2; else \+ b := b/2; fi;\n\nif (Im(z) = 0) then d := 1; else d := 1.3*abs(Im(z)) ; fi; \nc := - d;\nif (Im(z) > 0) then c:= c/2; else d :=d/2; fi ; \n\nAxes := plot(0, x = a..b, y = c..d, color = black, scaling = c onstrained):\n\nPt := plottools[disk]([ Re(z), Im(z) ], 1/3, color=red ):\n \nRun := plot( [[ 0, Im(z)], [Re(z), Im(z)]], color = blue, l inestyle = 2 );\nRise := plot( [[ Re(z), 0],[Re(z), Im(z)] ], \n \+ color = blue, linestyle = 2 );\n\nplots[display](Axe s,Pt, Run, Rise);\nend proc:" }}}}{SECT 0 {PARA 4 "" 0 "" {TEXT -1 36 " 1. The Origin of Imaginery Numbers" }}{PARA 0 "" 0 "" {TEXT -1 77 " \nThere are no real numbers, which upon being squared yield negative n umbers.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 12 "x^2 = - 1; " } }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 11 "x^2 = - 9; " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 12 "x^2 = - 12; " }}}{PARA 0 "" 0 "" {TEXT -1 99 "\nTo solve these we can \"invent\" a new number that will help us make some sense of these equations.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 9 "sqrt(-1);" }}}{PARA 0 "" 0 "" {TEXT -1 241 "\nThi s simple definition gives us a way to solve the kinds of problems we s aw above. When we solve equations with positive constants like this, w e get both a plus and minus answer. And so it is with solving equation s with negative constants.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 21 "x^2 = + 25; solve(%);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 20 "x^2 = - 1; solve(%);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 20 "x^2 = - 9; solve(%);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 21 "x^ 2 = - 12; solve(%);" }}}{PARA 0 "" 0 "" {TEXT -1 74 "\nNote that i (I \+ in Maple) has the property that when squared it gives -1. " }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 4 "I^2;" }}}{PARA 0 "" 0 "" {TEXT -1 118 "\nClearly this is not a real number since no real numbers which h ave this property. We call numbers are multiples of i " }{TEXT 259 18 "imaginary numbers." }{TEXT -1 368 " This name is not to be taken too \+ literally. Gauss, one of the originators of imaginary numbers, later w ished that they be called something else to avoid the whimsical imager y of that name. However, the name has taken hold and we are stuck with it now. Although it is not evident now, rest assured that imaginary n umbers are used in many, many real world applications." }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 60 "`Examples of imaginary uumbers :`;I ; 3*I; -13*I; sqrt(17)*I;" }}}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{SECT 0 {PARA 4 "" 0 "" {TEXT -1 32 " 2. Powers of Imaginery Numbers" }} {PARA 0 "" 0 "" {TEXT -1 211 "\nIf we look at the powers of imaginary \+ numbers, we will see some interesting patterns. The first four have fo ur distinct values. However, if we look at the higher powers we see th at the same four values repeat.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 16 "I^k $ k = 1..4 ;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 17 "I^k $ k = 1..20 ;" }}}{PARA 0 "" 0 "" {TEXT -1 78 "\n In fact, i, to any power ( of a natural number) is one of these four v alues.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 35 "I^(111); I^(222) ; I^(333); I^(444);" }}}{PARA 0 "" 0 "" {TEXT -1 200 "\n\nWhat about n egative exponents? Since 1/i = (i^3)/(i^4) = i^3/1 = i^3 = -i, the neg ative exponents simply give the negative of the value given by the pos itive exponent. Thats really unusual isn't it?" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 4 "1/I;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 20 "I^(-k) $ k = 1..20 ;" }}}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{SECT 0 {PARA 4 "" 0 "" {TEXT -1 34 " 3. The Origin of Complex Numbers" }} {PARA 0 "" 0 "" {TEXT -1 138 "\nRecall that when we have a quadratic e quation, and use the quadratic formula to solve it, we end up with a s quare root of D = b^2 - 4ac.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 34 "a*x^2 + b*x + c = 0; solve( %, x);" }}}{PARA 0 "" 0 "" {TEXT -1 46 "\nThis works out well if D is positive or zero." }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 62 "3*x^2 + 7*x - 2 = 0; \nD = 7^2 - 4*3*(-2); \nx = solve( %%, x);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 65 "5* x^2 - 30*x + 45 = 0; \nD = (-30)^2 - 4*5*45; \nx = solve( %%, x);" }}} {PARA 0 "" 0 "" {TEXT -1 118 "\n\n However, if D is negative, then thi s means that we'll have the square of a negative number as part of the solution." }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 57 "x^2 + 3*x + 5 \+ = 0; \nD = 3^2 - 4*1*5; \nx = solve( %%, x);" }}}{PARA 0 "" 0 "" {TEXT -1 59 "\nNumbers which are part real and part imaginary are coll ed " }{TEXT 260 15 "complex numbers" }{TEXT -1 110 ". They are neither purely real, nor purely imaginary - they are a combination of both. H ere are some examples." }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 8 "3 + 4*I;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 8 "-13 + I;" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 18 "41 - 10*sqrt(2)*I;" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 9 "1 + Pi*I;" }}}{PARA 0 "" 0 " " {TEXT -1 2 "\n " }}}{SECT 0 {PARA 4 "" 0 "" {TEXT -1 36 " 4. Operat ions with Complex Numbers" }}{PARA 0 "" 0 "" {TEXT -1 129 "\nWe can tr eat complex numbers just as we treat real numbers and add, subtract, m ultiply or divide them - with a few precautions.\n" }}{PARA 0 "" 0 "" {TEXT -1 5 " " }}{PARA 0 "" 0 "" {TEXT 263 37 " Complex Addi tion & Subtraction" }}{PARA 0 "" 0 "" {TEXT -1 226 "\nNotice that the \+ real parts combine and imaginary parts combine, but two don't mix. Its much the same as combining like terms. Note that its possible to add \+ two complex numbers and get a purely real or purely imaginary number. " }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 24 "(10 + 20*I) + (3 + 7*I); " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 24 "(4 - 4*I) + (-11 + 6*I) ;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 26 "(10 + 20*I) + (-10 - 8 *I);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 24 "(-9 + 17*I) + (9+ 1 7*I);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 26 "(30 + 40*I) - (35 \+ + 35*I);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 27 "(-10 + 31*I) - \+ (10 - 28*I);" }}}{PARA 0 "" 0 "" {TEXT -1 5 " " }}{PARA 0 "" 0 "" {TEXT 264 39 " Complex Multiplication & Powers" }}{PARA 0 "" 0 "" {TEXT -1 237 "\nComplex numbers are much like binomials. When multi plying two binomials we would use the FOIL method, andn so it is with \+ complex numbers too. The only thing, is that I^2 = -1. And so there is a little more simplification at the the end." }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 35 "(4 + 5*x)*(6 + 7*x): % = expand(%);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 20 "(4 + 5*I)*(6 + 7*I);" }}}{PARA 0 " " 0 "" {TEXT -1 55 "\nNotice that 24 - 35*I^2 = 24 - 35*(-1) = 4 + 35 \+ = 58.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 24 "(13 - 4*I)*(12 + 11*I);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 22 "(7 + 2*I)*(8 + 3*I);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 22 "(1 + 4*I)*(1 - 2 1*I);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 14 "(100 + 7*I)^2;" }} }{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 14 "(100 - 7*I)^2;" }}}{PARA 0 "" 0 "" {TEXT -1 2 "\n " }}}{SECT 0 {PARA 4 "" 0 "" {TEXT -1 33 " 5. \+ Simplifying Complex Numbers " }}{PARA 0 "" 0 "" {TEXT -1 9 "\n \+ " }{TEXT 261 19 "Conjugate Principle" }{TEXT -1 315 "\n\nNotice that i f we multiply a complex number times its conjugate - the same number w ith the sign on the imaginary part reversed - we get a purely real num ber. It works much the same way that conjugates of radical expressions works to eliminate radical expressions - in this case I = sqrt(-1) - \+ from an expression.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 20 "(3 \+ + 4*I)*(3 - 4*I);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 24 "(17 + \+ 29*I)*(17 - 29*I);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 47 "(sqrt (5) + 2*I)*(sqrt(5) - 2*I): % = expand(%);" }}}{EXCHG {PARA 0 "> " 0 " " {MPLTEXT 1 0 22 "(1 + 10*I)*(1 - 10*I);" }}}{EXCHG {PARA 0 "> " 0 " " {MPLTEXT 1 0 22 "(20 + 3*I)*(20 - 3*I);" }}}{EXCHG {PARA 0 "> " 0 " " {MPLTEXT 1 0 59 "(sqrt(3) + sqrt(5)*I)*(sqrt(3) - sqrt(5)*I): % = ex pand(%);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{PARA 0 "" 0 "" {TEXT -1 56 "\n \nNote that Maple can find the conjugate automatically.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 36 "z:= 3 + 20*I; zcon := conjugate(z) ;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 7 "z*zcon;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 45 "z:= 50 - 13*I; zcon := conjugate( z);z*zcon;" }}}{PARA 0 "" 0 "" {TEXT -1 5 " " }}{PARA 0 "" 0 "" {TEXT 262 21 " Complex Divsion" }}{PARA 0 "" 0 "" {TEXT -1 242 " \nThe conjugate principle can be used to \"divide\" complex numbers. A ctually, we'll perform an operation more akin to rationalizing the den ominator than dividing. But the result will be the quotient nonetheles s.\n\nMaple does this automatically.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 21 "(3 + 10*I)/(7 - 4*I);" }}}{PARA 0 "" 0 "" {TEXT -1 121 " \nWe can also do it manually - by multiplying top and bottom of \+ the fraction by the complex conjugate of the denominator." }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 32 "top := 3 + 10*I;\nbot := 7 - 4*I;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 27 "botcon := conjugate( bot \+ );" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 29 "top*botcon; bot*botco n; %%/%;" }}}{PARA 0 "" 0 "" {TEXT -1 27 " \n\nHere is another example " }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 22 "(2 + 1*I)/(7 - 4*I); \+ " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 32 "top := 2 + 1*I;\nbot := 7 - 4*I; " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 88 "botcon := con jugate( bot );\ntop*botcon: \nbot*botcon: \n`top `= %%, `bottom `= %; \+ \n%%%/%%;" }}}{PARA 0 "" 0 "" {TEXT -1 2 "\n " }}}{SECT 0 {PARA 4 "" 0 "" {TEXT -1 48 " 6. Geometric Interpretation of Complex Numbers" }} {PARA 0 "" 0 "" {TEXT -1 192 "\nThere is a graphic way of representing complex numbers. The real part is marked off on the x axis, and the i maginary part is marked off on the y axis. This defined a unique point on a plane.\n" }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 33 "z := 3 + 4 *I;\nComplexPlot( %); \n" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 31 "z := -8 + 3*I;\nComplexPlot( %);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 30 "z := 9 - 4*I;\nComplexPlot( %);" }}}{PARA 0 "" 0 "" {TEXT -1 64 "\nNotice that conjugates appear as reflections across the x axis." }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 78 "3 + 4*I, 3 - 4*I ;\nplots[display](ComplexPlot( 3 + 4*I),ComplexPlot( 3 - 4*I));" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 80 "-8 + 2*I, -8 - 2*I;\nplots[d isplay](ComplexPlot( -8+ 2*I),ComplexPlot(-8 - 2*I));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 62 "2*I, -2*I;\nplots[display](ComplexP lot(2*I),ComplexPlot(-2*I));" }}}{PARA 0 "" 0 "" {TEXT -1 86 "\nAnothe r interesting thing we can do is to plot two complex numbers and their product." }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 139 "z1 := 1 + 4*I; z2 := 4 - 1*I;\nplots[display]( ComplexPlot( z1),\n \+ ComplexPlot( z2),\n ComplexPlot( z1*z2) );" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 175 "z1 := 2*(1 + I)/evalf(sqrt(2)); z2 := 3*(1 + evalf(sqrt(3))*I)/2;\nplots[display]( ComplexPlot( z1),\n \+ ComplexPlot( z2),\n ComplexPlot( z1*z2 ) );" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 139 "z1 := 2 + 2*I; z2 \+ := 1 - 1*I;\nplots[display]( ComplexPlot( z1),\n Comp lexPlot( z2),\n ComplexPlot( z1*z2) );" }}}{PARA 0 "" 0 "" {TEXT -1 2 "\n " }}}{PARA 0 "" 0 "" {TEXT 265 36 "\n \251 2002 Waterloo Maple Inc " }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{MARK "5 2 0 0" 185 }{VIEWOPTS 1 1 0 1 1 1803 1 1 1 1 }{PAGENUMBERS 0 1 2 33 1 1 }