{VERSION 2 3 "IBM INTEL NT" "2.3" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 }{CSTYLE "" -1 256 "" 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 } {CSTYLE "" -1 257 "" 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 258 "" 0 1 0 0 0 0 1 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 }{CSTYLE "" -1 260 "" 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 } {CSTYLE "" -1 261 "" 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 262 "" 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 263 "" 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 }{CSTYLE "" -1 264 "" 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 } {CSTYLE "" -1 265 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 266 "" 0 1 0 0 0 0 1 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 267 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 268 "" 0 1 0 0 0 0 0 1 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 "Title" 0 18 1 {CSTYLE " " -1 -1 "" 1 18 0 0 0 0 0 1 1 0 0 0 0 0 0 }3 0 0 -1 12 12 0 0 0 0 0 0 19 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 }{PSTYLE "" 0 257 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 18 "" 0 "" {TEXT -1 32 "Solving a Transendental E quation" }}{PARA 256 "" 0 "" {TEXT -1 19 "Original Version: " }{TEXT 256 15 "Earl C. Swallow" }{TEXT -1 10 " 7/22/97" }}{PARA 257 "" 0 " " {TEXT -1 38 "Revised and Annotated: ECS 10/11/99" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 115 "This worksheet is an \+ example of solving a (rather simple) transendental equation which has \+ no closed-form solution." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 " " 0 "" {TEXT -1 13 "The equation " }{TEXT 258 17 "sin(x) = x*cos(x)" } {TEXT -1 77 " gives the positions of diffraction maxima for single-sli t diffraction (here " }{TEXT 259 1 "x" }{TEXT -1 93 " is the diffracti on angle). It herefore occurs is acoustics, optics, and quantum mecha nics (" }{TEXT 257 4 "i.e." }{TEXT -1 89 ", wherever there are waves). It has no closed-form solution. By dividing both sides by " }{TEXT 260 6 "cos(x)" }{TEXT -1 24 ", it can be turned into " }{TEXT 261 10 " tan(x) = x" }{TEXT -1 33 ", which is a bit more convenient." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 8 "restart ;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 16 "assume(x, real);" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 25 "eq1 := sin(x) = x*cos(x);" } }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 18 "eq2 := tan(x) = x;" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 12 "with(plots):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 49 "plot([x,tan(x)], x=0..25, y=0..25, \+ discont=true);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 61 "Let's look at t he first couple of intersections more closely." }}}{EXCHG {PARA 0 "> \+ " 0 "" {MPLTEXT 1 0 47 "plot([x,tan(x)], x=0..8, y=0..8, discont=true) ;" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 61 "So we can read from the grap h that the first 3 solutions are " }{TEXT 265 7 "roughly" }{TEXT -1 75 " x1 = 0, x2 = 4.46, x3 = 7.68 . Thinking about tan(x), it has asy mptotes (" }{TEXT 263 4 "i.e." }{TEXT -1 62 ", it goes off to infinity ) at 0.5*Pi, 1.5*Pi, 2.5*Pi, 3.5*Pi, " }{TEXT 262 3 "etc" }{TEXT -1 89 ". Recognizing that x2 is a little less than 1.5*Pi and x3 is a li ttle less than 2.5*Pi, " }{TEXT 264 4 "etc." }{TEXT -1 70 ", we see th at successive solutioons will be between N*Pi and (N+1)*Pi." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 28 "So now go for the solutions." }}}{EXCHG {PARA 0 "> \+ " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 33 " x2 := fsolve(eq1, x, 1*Pi..2*Pi);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 13 "evalf(x2/Pi);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "\"/1.5;" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 41 "So this is just a bit less than 1.5*Pi. " }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT 267 44 "Now you get the next few. Also try it with " } {TEXT 266 3 "eq2" }{TEXT 268 22 " and see what happens." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 " " {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 " " {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}}{MARK "24 0 0" 0 } {VIEWOPTS 1 1 0 1 1 1803 }