It seems assigning change:=f2 is your problem.  Try f2:=change instead.

Maybe lprint?

plot([cos(3*t), sin(2*t), t = 0 .. 2*Pi]);

lprint(%);
PLOT(CURVES(Matrix(209, 2, {(1, 1) = HFloat(1.), (2, 1) = HFloat(.995093264101945540), (2, 2) = HFloat(0.660209573197723110e-1), (3, 1) = HFloat(.982874948801488735), (3, 2) = HFloat(.123241184241304202), (4, 1) = HFloat(.960415331794754912), (4, 2) = HFloat(.187095559833458880), (5, 1) = HFloat(.928692888370737157), (5, 2) = HFloat(.250583123026205390), (6, 1) = HFloat(.888341049365922508), (6, 2) = HFloat(.312716031931642657), (7, 1) = HFloat(.843435582881161494), (7, 2) = HFloat(.369155248626400478), (8, 1) = HFloat(.789737481048331080), (8, 2) = HFloat(.426189998289056848), (9, 1) = HFloat(.726988273906466032), (9, 2) = HFloat(.483440255170793975), (10, 1) = HFloat(.657713718477610843), (10, 2) = HFloat(.538518445847828708), (11, 1) = HFloat(.580124538604127493), (11, 2) = HFloat(.592863355868342379), (12, 1) = HFloat(.507061588853425005), (12, 2) = HFloat(.638603964793882595), (13, 1) = HFloat(.420238020776815213), (13, 2) = HFloat(.687513346078893139), (14, 1) = HFloat(.328996184828279803), (14, 2) = HFloat(.733667728275790187), (15, 1) = HFloat(.238041581986947248), (15, 2) = HFloat(.775157844789451933), (16, 1) = HFloat(.153568372599895503), (16, 2) = HFloat(.810152318374346758), (17, 1) = HFloat(0.516903761583032209e-1), (17, 2) = HFloat(.848276396747285943), (18, 1) = HFloat(-0.350807193735846248e-1), (18, 2) = HFloat(.877483383648545501), (19, 1) = HFloat(-.135639118077677007), (19, 2) = HFloat(.907755898501108049), (20, 1) = HFloat(-.223529985692667771), (20, 2) = HFloat(.931125642447514057), (21, 1) = HFloat(-.317881575278769035), (21, 2) = HFloat(.952961215633009173), (22, 1) = HFloat(-.404900842257057803), (22, 2) = HFloat(.969970900850029349), (23, 1) = HFloat(-.491924216375459078), (23, 2) = HFloat(.983712180075785425), (24, 1) = HFloat(-.567748258469063294), (24, 2) = HFloat(.992677943036860744), (25, 1) = HFloat(-.644426299186268925), (25, 2) = HFloat(.998390136485883373), (26, 1) = HFloat(-.717714250173252410), (26, 2) = HFloat(.999949223787556019), (27, 1) = HFloat(-.775669174171986331), (27, 2) = HFloat(.997671804246988203), (28, 1) = HFloat(-.831619946383563624), (28, 2) = HFloat(.991421294045069290), (29, 1) = HFloat(-.881666027915066430), (29, 2) = HFloat(.980855601678915945), (30, 1) = HFloat(-.922547877554730666), (30, 2) = HFloat(.966521170869912294), (31, 1) = HFloat(-.954145429505132481), (31, 2) = HFloat(.948942736353007077), (32, 1) = HFloat(-.979732108253810963), (32, 2) = HFloat(.925232759205969923), (33, 1) = HFloat(-.987902672045105401), (33, 2) = HFloat(.913171937940988276), (34, 1) = HFloat(-.993985648764305951), (34, 2) = HFloat(.900253401738528192), (35, 1) = HFloat(-.998161690392944556), (35, 2) = HFloat(.885527019193549148), (36, 1) = HFloat(-.999933202852693825), (36, 2) = HFloat(.869852443315878299), (37, 1) = HFloat(-.997006102055733034), (37, 2) = HFloat(.839084123645368218), (38, 1) = HFloat(-.984786488226064516), (38, 2) = HFloat(.802074455362625338), (39, 1) = HFloat(-.964786753172529044), (39, 2) = HFloat(.764170478498252037), (40, 1) = HFloat(-.935254589504708078), (40, 2) = HFloat(.721513059049358363), (41, 1) = HFloat(-.898112516187038801), (41, 2) = HFloat(.676970729790365766), (42, 1) = HFloat(-.850824619142301453), (42, 2) = HFloat(.627523533269496392), (43, 1) = HFloat(-.797570978035496481), (43, 2) = HFloat(.577371030739956326), (44, 1) = HFloat(-.735786610659668106), (44, 2) = HFloat(.523725493801580844), (45, 1) = HFloat(-.667760211506508328), (45, 2) = HFloat(.468386642662180275), (46, 1) = HFloat(-.599855216887644649), (46, 2) = HFloat(.415852585744740932), (47, 1) = HFloat(-.516368371666899195), (47, 2) = HFloat(.353898893434316020), (48, 1) = HFloat(-.437236627092241481), (48, 2) = HFloat(.297127125152112148), (49, 1) = HFloat(-.348976342827391262), (49, 2) = HFloat(.235421628643554953), (50, 1) = HFloat(-.261475977430020934), (50, 2) = HFloat(.175454466133063841), (51, 1) = HFloat(-.161763476824103719), (51, 2) = HFloat(.108106580473264227), (52, 1) = HFloat(-0.740213527132065063e-1), (52, 2) = HFloat(0.493726628305415013e-1), (53, 1) = HFloat(0.262293744673981893e-1), (53, 2) = HFloat(-0.174873638795113792e-1), (54, 1) = HFloat(.117393216169258907), (54, 2) = HFloat(-0.783626027905274108e-1), (55, 1) = HFloat(.215961974470104234), (55, 2) = HFloat(-.144609155232220787), (56, 1) = HFloat(.299311261051054600), (56, 2) = HFloat(-.201263025576119164), (57, 1) = HFloat(.391489098405798708), (57, 2) = HFloat(-.264963626440157696), (58, 1) = HFloat(.476950203554007413), (58, 2) = HFloat(-.325418569365158894), (59, 1) = HFloat(.558064738412816452), (59, 2) = HFloat(-.384532353352742717), (60, 1) = HFloat(.633890362602178681), (60, 2) = HFloat(-.441899748072451137), (61, 1) = HFloat(.701413171156469617), (61, 2) = HFloat(-.495362579944167714), (62, 1) = HFloat(.767890284790246458), (62, 2) = HFloat(-.551110184112867052), (63, 1) = HFloat(.824375231430874322), (63, 2) = HFloat(-.602049173252518388), (64, 1) = HFloat(.876026995964009569), (64, 2) = HFloat(-.653127725230104206), (65, 1) = HFloat(.915478127479820492), (65, 2) = HFloat(-.696945843641809448), (66, 1) = HFloat(.950612588090555821), (66, 2) = HFloat(-.742505055908345368), (67, 1) = HFloat(.975626490690282622), (67, 2) = HFloat(-.783143762911385988), (68, 1) = HFloat(.991931968635061834), (68, 2) = HFloat(-.820597266232610645), (69, 1) = HFloat(.999585319789284887), (69, 2) = HFloat(-.856266505733220828), (70, 1) = HFloat(.998094016522872329), (70, 2) = HFloat(-.885869493765740090), (71, 1) = HFloat(.994160830774133308), (71, 2) = HFloat(-.899785162623916501), (72, 1) = HFloat(.988090583676968670), (72, 2) = HFloat(-.912841105840068390), (73, 1) = HFloat(.978921728563026061), (73, 2) = HFloat(-.926242794912090828), (74, 1) = HFloat(.967187663656392194), (74, 2) = HFloat(-.938565611925027743), (75, 1) = HFloat(.939514541203616105), (75, 2) = HFloat(-.958088936782832024), (76, 1) = HFloat(.902870173151799960), (76, 2) = HFloat(-.974270660654016685), (77, 1) = HFloat(.857288501687358595), (77, 2) = HFloat(-.986736072040474421), (78, 1) = HFloat(.808354130363334034), (78, 2) = HFloat(-.994600140549084077), (79, 1) = HFloat(.749214705766426348), (79, 2) = HFloat(-.999160233538684439), (80, 1) = HFloat(.683917914786050796), (80, 2) = HFloat(-.999768472352535742), (81, 1) = HFloat(.607436507481678656), (81, 2) = HFloat(-.996097108568060996), (82, 1) = HFloat(.534848109093290169), (82, 2) = HFloat(-.989159193130524250), (83, 1) = HFloat(.445932284292002323), (83, 2) = HFloat(-.976879206933512156), (84, 1) = HFloat(.361677898743807680), (84, 2) = HFloat(-.961910954801300955), (85, 1) = HFloat(.275289484206780899), (85, 2) = HFloat(-.943528610575696702), (86, 1) = HFloat(.179862932911773604), (86, 2) = HFloat(-.919875247348552305), (87, 1) = HFloat(0.823135670878773901e-1), (87, 2) = HFloat(-.892173946003792184), (88, 1) = HFloat(-0.715923643143954493e-2), (88, 2) = HFloat(-.863629116200008040), (89, 1) = HFloat(-.102096312896319180), (89, 2) = HFloat(-.829948042850447654), (90, 1) = HFloat(-.193862362832848245), (90, 2) = HFloat(-.793861120317075342), (91, 1) = HFloat(-.291427682463165472), (91, 2) = HFloat(-.751314442328326781), (92, 1) = HFloat(-.373504758209699750), (92, 2) = HFloat(-.711765148609128318), (93, 1) = HFloat(-.464245107585174510), (93, 2) = HFloat(-.663391994916401329), (94, 1) = HFloat(-.545332107735446603), (94, 2) = HFloat(-.615227126771057287), (95, 1) = HFloat(-.620892281187063522), (95, 2) = HFloat(-.565146302134166501), (96, 1) = HFloat(-.691128770153389027), (96, 2) = HFloat(-.512846920317007848), (97, 1) = HFloat(-.756586153184119259), (97, 2) = HFloat(-.457468810033391238), (98, 1) = HFloat(-.818504578353094425), (98, 2) = HFloat(-.396770099996740677), (99, 1) = HFloat(-.867999692433419900), (99, 2) = HFloat(-.339536796759702386), (100, 1) = HFloat(-.909602992964738011), (100, 2) = HFloat(-.281777211418164752), (101, 1) = HFloat(-.945713944592248001), (101, 2) = HFloat(-.218887944828852737), (102, 1) = HFloat(-.972800641317989490), (102, 2) = HFloat(-.155214744000589155), (103, 1) = HFloat(-.989290339391220019), (103, 2) = HFloat(-0.975010830516318955e-1), (104, 1) = HFloat(-.999071706820651273), (104, 2) = HFloat(-0.287236868334883391e-1), (105, 1) = HFloat(-.999057373303013807), (105, 2) = HFloat(0.289445676979894866e-1), (106, 1) = HFloat(-.989562010713673668), (106, 2) = HFloat(0.962581899740645730e-1), (107, 1) = HFloat(-.971055471764343259), (107, 2) = HFloat(.160098461874967096), (108, 1) = HFloat(-.946876818902685380), (108, 2) = HFloat(.216547531764909762), (109, 1) = HFloat(-.911290461770500437), (109, 2) = HFloat(.279166555016422957), (110, 1) = HFloat(-.866820740398964507), (110, 2) = HFloat(.341022077787115963), (111, 1) = HFloat(-.814366945698000944), (111, 2) = HFloat(.401150529926342814), (112, 1) = HFloat(-.758862301943241335), (112, 2) = HFloat(.455399853250309461), (113, 1) = HFloat(-.694912962690416136), (113, 2) = HFloat(.509839588760538698), (114, 1) = HFloat(-.622429912169550459), (114, 2) = HFloat(.564066152125074827), (115, 1) = HFloat(-.544419988611536954), (115, 2) = HFloat(.615798664311906552), (116, 1) = HFloat(-.458937986297073330), (116, 2) = HFloat(.666371127580410727), (117, 1) = HFloat(-.379901758909653553), (117, 2) = HFloat(.708523809513541214), (118, 1) = HFloat(-.287509500615067526), (118, 2) = HFloat(.753112602378217311), (119, 1) = HFloat(-.191959418220285449), (119, 2) = HFloat(.794646677475388197), (120, 1) = HFloat(-0.981088171354586591e-1), (120, 2) = HFloat(.831435491015080852), (121, 1) = HFloat(-0.120961004499473106e-1), (121, 2) = HFloat(.861965155992681642), (122, 1) = HFloat(0.902457096602296283e-1), (122, 2) = HFloat(.894558903914745351), (123, 1) = HFloat(.176244582389329302), (123, 2) = HFloat(.918911015468448444), (124, 1) = HFloat(.274568180373232940), (124, 2) = HFloat(.943362799860770540), (125, 1) = HFloat(.359299052333536428), (125, 2) = HFloat(.961444789047370185), (126, 1) = HFloat(.448937935648393349), (126, 2) = HFloat(.977355768217095355), (127, 1) = HFloat(.530298376559004248), (127, 2) = HFloat(.988626590324497179), (128, 1) = HFloat(.610253528329505301), (128, 2) = HFloat(.996303271681065028), (129, 1) = HFloat(.678596392773996193), (129, 2) = HFloat(.999652451922633301), (130, 1) = HFloat(.746212838049202798), (130, 2) = HFloat(.999279183113629066), (131, 1) = HFloat(.809086638780554424), (131, 2) = HFloat(.994513634808954938), (132, 1) = HFloat(.857225232338885368), (132, 2) = HFloat(.986749366985044563), (133, 1) = HFloat(.901879357489389188), (133, 2) = HFloat(.974614971110934758), (134, 1) = HFloat(.939601235770873733), (134, 2) = HFloat(.958040566059456977), (135, 1) = HFloat(.967894375197106083), (135, 2) = HFloat(.937920591653075397), (136, 1) = HFloat(.978445394198942275), (136, 2) = HFloat(.926824514348714934), (137, 1) = HFloat(.986919187167190626), (137, 2) = HFloat(.914853846350839106), (138, 1) = HFloat(.993872549167743147), (138, 2) = HFloat(.900551555303991780), (139, 1) = HFloat(.998224771172738001), (139, 2) = HFloat(.885201625085295207), (140, 1) = HFloat(.999907229218049975), (140, 2) = HFloat(.870530123433630010), (141, 1) = HFloat(.999476732754708164), (141, 2) = HFloat(.855040959018391833), (142, 1) = HFloat(.991493866143389857), (142, 2) = HFloat(.819295786251743263), (143, 1) = HFloat(.976010307005786060), (143, 2) = HFloat(.783871171306493308), (144, 1) = HFloat(.950256661933032709), (144, 2) = HFloat(.741993645657856304), (145, 1) = HFloat(.917818190727948457), (145, 2) = HFloat(.699739586695532489), (146, 1) = HFloat(.875705748307880838), (146, 2) = HFloat(.652791582113811497), (147, 1) = HFloat(.826789697628834475), (147, 2) = HFloat(.604324382047172204), (148, 1) = HFloat(.767845059519881801), (148, 2) = HFloat(.551070911013765485), (149, 1) = HFloat(.704114699808206401), (149, 2) = HFloat(.497560137692068472), (150, 1) = HFloat(.632475830420674567), (150, 2) = HFloat(.440806462822373124), (151, 1) = HFloat(.555624328424223934), (151, 2) = HFloat(.382723504604894627), (152, 1) = HFloat(.480511671748108882), (152, 2) = HFloat(.327974528230208562), (153, 1) = HFloat(.389899709807566441), (153, 2) = HFloat(.263853512652095279), (154, 1) = HFloat(.305479198730463530), (154, 2) = HFloat(.205486799561757499), (155, 1) = HFloat(.212757754732972842), (155, 2) = HFloat(.142444814262494696), (156, 1) = HFloat(.122163067946142886), (156, 2) = HFloat(0.815553095377624937e-1), (157, 1) = HFloat(0.203939098100098110e-1), (157, 2) = HFloat(0.135964635506402240e-1), (158, 1) = HFloat(-0.679405883589561527e-1), (158, 2) = HFloat(-0.453131224544987693e-1), (159, 1) = HFloat(-.167520870928223709), (159, 2) = HFloat(-.111974318859801747), (160, 1) = HFloat(-.256835678931248201), (160, 2) = HFloat(-.172300293829411311), (161, 1) = HFloat(-.352048697882217765), (161, 2) = HFloat(-.237546579692993948), (162, 1) = HFloat(-.431407930252718452), (162, 2) = HFloat(-.293005264509637653), (163, 1) = HFloat(-.517846220784493050), (163, 2) = HFloat(-.354975245017543406), (164, 1) = HFloat(-.596604630548027814), (164, 2) = HFloat(-.413391645989387824), (165, 1) = HFloat(-.669944358066613010), (165, 2) = HFloat(-.470116313883948200), (166, 1) = HFloat(-.737023027338493231), (166, 2) = HFloat(-.524763019572474398), (167, 1) = HFloat(-.795274565623967478), (167, 2) = HFloat(-.575302194904628972), (168, 1) = HFloat(-.850861712390843072), (168, 2) = HFloat(-.627560177199392166), (169, 1) = HFloat(-.896222605548881779), (169, 2) = HFloat(-.674868457399333321), (170, 1) = HFloat(-.935490032503407898), (170, 2) = HFloat(-.721820286664437982), (171, 1) = HFloat(-.963230229146209815), (171, 2) = HFloat(-.761647060563439449), (172, 1) = HFloat(-.984984762427186689), (172, 2) = HFloat(-.802529998039201664), (173, 1) = HFloat(-.996868790332053556), (173, 2) = HFloat(-.838446724351124772), (174, 1) = HFloat(-.999887970842842200), (174, 2) = HFloat(-.870971772918978981), (175, 1) = HFloat(-.997944658660394945), (175, 2) = HFloat(-.886602839079551064), (176, 1) = HFloat(-.993590400180439204), (176, 2) = HFloat(-.901281819053078692), (177, 1) = HFloat(-.987456034194965637), (177, 2) = HFloat(-.913945815351264401), (178, 1) = HFloat(-.979297876550140778), (178, 2) = HFloat(-.925777229337745866), (179, 1) = HFloat(-.956344743548646292), (179, 2) = HFloat(-.947367448869784856), (180, 1) = HFloat(-.921465139823633539), (180, 2) = HFloat(-.966997859176745633), (181, 1) = HFloat(-.881546519240037130), (181, 2) = HFloat(-.980888459750203889), (182, 1) = HFloat(-.832894562745947198), (182, 2) = HFloat(-.991219790139763246), (183, 1) = HFloat(-.775746722506624686), (183, 2) = HFloat(-.997666214135419449), (184, 1) = HFloat(-.716846506997171340), (184, 2) = HFloat(-.999957245606440503), (185, 1) = HFloat(-.647876575260122656), (185, 2) = HFloat(-.998556546300095382), (186, 1) = HFloat(-.573717438221209797), (186, 2) = HFloat(-.993251674169345455), (187, 1) = HFloat(-.488829425272471141), (187, 2) = HFloat(-.983283885524348533), (188, 1) = HFloat(-.409810122357457784), (188, 2) = HFloat(-.970836294914462661), (189, 1) = HFloat(-.314693271869310065), (189, 2) = HFloat(-.952279727923407204), (190, 1) = HFloat(-.226015047027563559), (190, 2) = HFloat(-.931744362076591504), (191, 1) = HFloat(-.136382360249396956), (191, 2) = HFloat(-.907965594101156181), (192, 1) = HFloat(-0.387553207809959721e-1), (192, 2) = HFloat(-.878656457849667616), (193, 1) = HFloat(0.596398641464917154e-1), (193, 2) = HFloat(-.845453640685242203), (194, 1) = HFloat(.148687986694261615), (194, 2) = HFloat(-.812077408376920884), (195, 1) = HFloat(.241932088878842516), (195, 2) = HFloat(-.773467153639162852), (196, 1) = HFloat(.330826976067736533), (196, 2) = HFloat(-.732788568211495961), (197, 1) = HFloat(.423948929915850481), (197, 2) = HFloat(-.685529097059929815), (198, 1) = HFloat(.501097422188309660), (198, 2) = HFloat(-.642139991866428783), (199, 1) = HFloat(.584987135988432216), (199, 2) = HFloat(-.589646768721602377), (200, 1) = HFloat(.658532716923785788), (200, 2) = HFloat(-.537907253647431860), (201, 1) = HFloat(.725638944707979405), (201, 2) = HFloat(-.484585448285424714), (202, 1) = HFloat(.786506547213669638), (202, 2) = HFloat(-.429353091420042354), (203, 1) = HFloat(.841556618713768190), (203, 2) = HFloat(-.371315313141940495), (204, 1) = HFloat(.891608559235583020), (204, 2) = HFloat(-.308174981261063963), (205, 1) = HFloat(.929568939609444200), (205, 2) = HFloat(-.249053664812155823), (206, 1) = HFloat(.959270841354030623), (206, 2) = HFloat(-.189766662182448170), (207, 1) = HFloat(.982205776992280066), (207, 2) = HFloat(-.125620483500565344), (208, 1) = HFloat(.995799859113089436), (208, 2) = HFloat(-0.610853875403885929e-1), (209, 1) = HFloat(1.), (209, 2) = HFloat(0.164082742812264922e-8)}, datatype = float[8], storage = rectangular, order = Fortran_order, shape = []), COLOUR(RGB, .47058824, 0., 0.54901961e-1, _ATTRIBUTE("source" = "mathdefault"))), AXESLABELS("", ""), VIEW(DEFAULT, DEFAULT))

Try this and see what you get.  I tried and haven't been able to get a different value which is good.

evalf(add(sin(k*1.), k = 1 .. 10000))

evalf(add(sin(1.*k), k = 1 .. 10000), 25);
                   1.633891021792462265108364

This seems to fix the randomness of the answer.

I think Preview is the command from tha audiotools package you need.  The y axes represents the amplitude.

also see http://www.maplesoft.com/applications/view.aspx?SID=5521&view=html&L=E

** I edited a deleted post to a comment which had been deleted to make it visible - it disappeared
** so luckily I was able to go back in my browser and find the content, I will add the content here.  Not sure why it was deleted by the author but it seems relevant to the topic under discussion

Titled - Example

Up to AudioTools, this can be done as follows.

audiofile := cat(kernelopts(datadir), "/audio/stereo.wav"):
seq([j, AudioTools:-Read(audiofile)[j]], j = 1 .. 10);
[1, Matrix(1, 2, [[-0.156250000000000e-1, .212598425196850]])],
[2, Matrix(1, 2, [[0., -.265625000000000]])],
[3, Matrix(1, 2, [[0.393700787401575e-1, .456692913385827]])],
[4, Matrix(1, 2, [[0.866141732283465e-1, -.703125000000000]])],
[5, Matrix(1, 2, [[.141732283464567, -.343750000000000]])],
[6, Matrix(1, 2, [[.196850393700787, -.335937500000000]])],
[7, Matrix(1, 2, [[.259842519685039, .275590551181102]])], 
[8, Matrix(1, 2, [[.322834645669291, .102362204724409]])], 
[9, Matrix(1, 2, [[.385826771653543, 0.236220472440945e-1]])],
[10, Matrix(1, 2, [[.440944881889764, .582677165354331]])]

The whole rtable contains 19962 rows up to

AudioTools:-Read(audiofile);
                    Vector[column](4, [` 1..19962 x 1..2 `*Array, `Data Type: `*float[8], `Storage:                  `*rectangular, `Order: `*C_order])

Each row corresponds to 0.4535147392e-4 s in view of

evalf(AudioTools:-Duration(AudioTools:-Read(audiofile)));
                          0.9053061224
(1/19962)*%;
                        0.00004535147392

Best regard,

Markiyan Hirnyk

First try a different .wav file.  If that works then there is a problem with your 440.wav file you are trying to Read. 

It's probable that your 440.wav wasn't written correctly or it's corrupt. 

You could load your 440.wav with one of a multitude of free audio editing softwares (ie. Audacity) and resave.

The reason the lines are fuzzy is because you have multiple lines overlaying one another in the 2d. 

change your range to 0..15 and you will see what I mean. 

It's a windows setting.  Windows -> control panel -> display and change the icon sizes. 

For example

with(ImageTools):
a:=Read("c:/yourimage.jpg"):
plot(x^2,axis=[gridlines=[10,color=black]],background=a) #x^2 is plotted over yourimage.jpg with gridlines

So you're saying given 3 equations with 3 unknowns and only have 2 of the solutions can we get the third?

Certainly, substitute the 2 solutions into any one of the equations to find the removed solution.

In terms of Maple, an example

a := 7*x+5*y-3*z = 16;
b := 3*x-5*y+2*z = -8;
c := 5*x+3*y-7*z = 0;
d:=solve({a,b,c})
                                   {x = 1, y = 3, z = 2}

So if the z solution was pulled away finding it just involves substituting into any one of the others, we'll use equation c here

solve(subs({d[1],d[2]},c),{z})
                                                 {z = 2}

I think the problem is the use of double if statements, try using elif or else.  Look here on the if help http://www.maplesoft.com/support/help/Maple/view.aspx?path=if

After 4 rides there is really no best possible time, that much variablity in the data you're almost at the limit.  Meaning the spread of times after 4 rides is almost 30 minutes saying it doesn't really matter when you show up after 2 hours, you're just as likely to arrive for a ride as any other time.  Nevertheless, here's one way using random selections from the given data.

monte-carlo_2_test.mw

So here's a start, for example x is some function of t

x := t -> t^2+t-3

x(5)
           27

and y is some other function of t

y:=t->3*t^3-4*t

y(2)
           16

t going from -n to n could be something like

for i from -5 to 5 do
  x(t):
end do;

or

seq(x(i),i=-5..5)
                   17, 9, 3, -1, -3, -3, -1, 3, 9, 17, 27

writedata is another command you could use.

Sounds like an operating system setting.  On windows you can change the icon setting sizes.

Definitely some sort of graphics issue.  Looks like it's gone to 256 colors.  See if you can manually change your graphics in windows. 

On what system are you using and what operating system?  It looks like windows 7.  Maybe you used some sort of compatibility mode or something.