{VERSION 5 0 "IBM INTEL LINUX" "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 }{PSTYLE "Normal" -1 0 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 }0 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }{PSTYLE "Heading 1" 0 3 1 {CSTYLE "" -1 -1 "" 1 18 0 0 0 0 0 1 0 0 0 0 0 0 0 1 }1 0 0 0 8 4 0 0 0 0 0 0 -1 0 }{PSTYLE "" 3 256 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 }3 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }} {SECT 0 {PARA 256 "" 0 "" {TEXT -1 32 "Double Integration and Summatio n" }}{PARA 0 "" 0 "" {TEXT -1 100 "Goal : Approximate the mass of a pl ate in the shape of the rectangular region bounded by the curves " }} {PARA 0 "" 0 "" {TEXT -1 50 "x=0, x=2, y=0, y=1. The density at (x,y) \+ is xy^2." }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 301 "restart:\nwith (plots): \nplate := implicitplot( \{x=0, x=2, y=0, y=1\}, x=0..2, y=0. .1,\n title=`find mass of this plate, d(x,y)=1+x+y`, \+ \+ color=red, thickness=2, scaling=constrained ):\ndi splay(plate);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 21 "Subdivisions of \+ plate" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 215 "vertlines := seq( x=i/5, \+ i=1..9):\nhorlines := seq( y=j/5, j=1..4):\nmesh := implicitplot( \{ v ertlines, horlines\}, x=0..2, y=0..1, \n color = blue, scaling=constrained ):\ndisplay( \{plate, mesh\} );" }}}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 53 "To find mass of this plate we make two approximations" }}{PARA 0 "" 0 "" {TEXT -1 45 "(i) subdivide region into squares with side h" }}{PARA 0 "" 0 "" {TEXT -1 146 "(ii) mass of plate ~= sum of mass of all squares in th e plate\nand note \n(iii) mass of each square ~= h^2 * density at \+ mid-pt of this square." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{EXCHG {PARA 0 "" 0 "" {TEXT -1 10 "Density is" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 25 "d := proc(x,y) x*y^2 end:" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 64 "The approximate mass of the plate for a subdivision of size h is" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 206 "mapprox := proc(h)\n l ocal total:\n total := h^2*sum( sum( d(i*h + h/2,j*h + h/2), \n i=0..2/h-1), j=0..1/h-1);\n \+ evalf(total);\n end: " }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 50 "So the approximate mass of the plate when h=0.1 is" }} {PARA 0 "> " 0 "" {MPLTEXT 1 0 13 "mapprox(0.5);" }}}{PARA 0 "" 0 "" {TEXT -1 80 "Decrease h from 0.1 to 0.01 - what is the approximate mas s. Decrease it further." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{EXCHG {PARA 0 "" 0 "" {TEXT -1 18 "The exact masss is" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 52 "M := Int( Int( d(x,y), x=0..2 ), y=0..1 );\nevalf(M); " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{MARK "2 0" 49 } {VIEWOPTS 1 1 0 1 1 1803 1 1 1 1 }{PAGENUMBERS 0 1 2 33 1 1 }