{VERSION 3 0 "IBM INTEL NT" "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 }} {SECT 0 {EXCHG {PARA 0 "" 0 "" {TEXT -1 19 "page 197 number 28:" }} {PARA 0 "" 0 "" {TEXT -1 64 "Find the shortest distance from the curve xy =4 to the origin." }}{PARA 0 "" 0 "" {TEXT -1 120 "First we plot y = 4/x, and let the distance function, d(x), to be the distance fro m the curve to the origin. Thus d(x)=" }{XPPEDIT 18 0 "sqrt(x^2+(4/x)^ 2);" "6#-%%sqrtG6#,&*$)%\"xG\"\"#\"\"\"F+*$)*&\"\"%\"\"\"%\"xG!\"\"\" \"#F+F+" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 80 "To minimize the functi on d(x) is equivalent to minimize d^2, let's call it e(x)." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 18 "e:= x->x^2+(4/x)^2;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 28 "f:=proc( x) diff(e(x),x) end;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 5 "f(x) ;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "simplify(f(x));" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 13 "factor(f(x));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 29 "plot(f(x),x=-3..3,y=-30..30);" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 247 "As we see from the graph of f (d erivative function of e(x)), we have a relative minimum for e(x) at \+ x = -2 and x =2. This means that the point (2, 2) is the point on xy = 4 which will result in the shortest distance. The shortest distance is " }{XPPEDIT 18 0 "sqrt(2^2+(4/2)^2);" "6#-%%sqrtG6#,&*$\"\"#\"\"# \"\"\"*$*&\"\"%F*\"\"#!\"\"\"\"#F*" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 28 "plot(4/x,x=-5..5,y=-10..10);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 12 "Problem #27:" }}{PARA 0 "" 0 "" {TEXT -1 92 "Suppose t hat a rectangle has its base on the x-axis and its two upper corners o n the curve " }{XPPEDIT 18 0 "y = 2(1-x^2);" "6#/%\"yG-\"\"#6#,&\"\" \"\"\"\"*$)%\"xG\"\"#F*!\"\"" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 54 "( a) What is the maximum perimeter of such a rectangle." }}{PARA 0 "" 0 "" {TEXT -1 54 "(b) Show that there is no minimum perimeter rectangle. " }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 32 "plot(2*(1-x^2),x=-5..5,y=-5..5);" }}}{EXCHG {PARA 0 " > " 0 "" {MPLTEXT 1 0 0 "" }}}}{MARK "14" 0 }{VIEWOPTS 1 1 0 1 1 1803 }