MATH383: A first course in differential equationsApril 2, 2020

Homework 11 Solution

Due date: April 9, 2020, 11:55PM.

Bibliography: Lesson 21, Trench, 3.1-3.3

  1. Exercises 1-5, p. 106

  2. Exercises 1-5, p. 124

  3. Exercise 13, p. 108

  4. Exercises 13, p. 126

Solutions

Here is a template for this numerical methods homework.

1. Euler's method. Ex.1. y'=f(x,y)=2x2+3y2-2, y(2)=1, h=0.05.

(%i1) 

f(x,y):=2*x^2+3*y^2-2$

(%i2) 

h:0.05$ x0:2$ y0:1$

(%i5) 

for i:1 thru 3 do
  ( x1: x0+h, y1: y0+h*f(x0,y0), x0: x1, y0: y1,
    display([i,x1,y1]) )$

[i,x1,y1]=[1,2.05,1.45]

[i,x1,y1]=[2,2.1,2.085625] [i,x1,y1]=[3,2.149999999999999,3.07909974609375]

(%i6) 


              

Ex. 2 y'=f(x,y)=y+x2+y2, y(0)=1, h=0.1.

(%i1) 

f(x,y):=y+sqrt(x^2+y^2)$

(%i2) 

h: 0.1$ x0: 0$ y0: 1$

(%i5) 

for i:1 thru 3 do
  ( x1: x0+h, y1: y0+h*f(x0,y0), x0: x1, y0: y1,
    display([i,x1,y1]) )$

[i,x1,y1]=[1,0.1,1.2]

[i,x1,y1]=[2,0.2,1.440415945787923] [i,x1,y1]=[3,0.3,1.729880994351281]

(%i6) 


              

Ex. 3. y'=f(x,y)=x2+y2-3y(x+1), y(0)=2, h=0.05.

(%i6) 

f(x,y):=x^2+y^2-3*y*(x+1)$

(%i7) 

h: 0.05$ x0: 0$ y0: 2$

(%i10) 

for i:1 thru 3 do
  ( x1: x0+h, y1: y0+h*f(x0,y0), x0: x1, y0: y1,
    display([i,x1,y1]) )$

[i,x1,y1]=[1,0.05,1.9]

[i,x1,y1]=[2,0.1,1.781375] [i,x1,y1]=[3,0.15,1.64661296953125]

(%i11) 


              

Ex. 4. y'=f(x,y)=(1+x)/(1-y2), y(2)=3, h=0.1.

(%i11) 

f(x,y):=(1+x)/(1-y^2)$

(%i12) 

h: 0.1$ x0: 2$ y0: 3$

(%i15) 

for i:1 thru 3 do
  ( x1: x0+h, y1: y0+h*f(x0,y0), x0: x1, y0: y1,
    display([i,x1,y1]) )$

[i,x1,y1]=[1,2.1,2.9625]

[i,x1,y1]=[2,2.2,2.922635827523157] [i,x1,y1]=[3,2.3,2.880205639458119]

(%i16) 


              

Ex. 5. y'=f(x,y)=sin(xy)-x2y, y(1)=π, h=0.2.

(%i11) 

f(x,y):=sin(x*y)-x^2*y$

(%i20) 

h: 0.2$ x0: 1$ y0: 3.1415$

(%i23) 

for i:1 thru 3 do
  ( x1: x0+h, y1: y0+h*f(x0,y0), x0: x1, y0: y1,
    display([i,x1,y1]) )$

[i,x1,y1]=[1,1.2,3.096399199852611]

[i,x1,y1]=[2,1.4,3.04516305809343] [i,x1,y1]=[3,1.6,2.987143119411182]

(%i24) 


              

2. Runge-Kutta method. Ex.1. y'=f(x,y)=2x2+3y2-2, y(2)=1, h=0.05.

(%i6) 

f(x,y):=2*x^2+3*y^2-2$

(%i7) 

h:0.05$ x0:2$ y0:1$

(%i10) 

for i:1 thru 3 do
  ( x1: x0+h,
        k1: h*f(x0,y0),
        k2: h*f(x0+0.5*h, y0+0.5*k1),
        k3: h*f(x0+0.5*h, y0+0.5*k2),
        k4: h*f(x0+h, y0+k3),
        y1: y0+(1/6)*(k1+2*k2+2*k3+k4),
        x0: x1, y0: y1,
    display([i,x1,y1]) )$

[i,x1,y1]=[1,2.05,1.550598189929713]

[i,x1,y1]=[2,2.1,2.469649728729797] [i,x1,y1]=[3,2.149999999999999,4.530350898626433]

(%i11) 


              

Ex. 2 y'=f(x,y)=y+x2+y2, y(0)=1, h=0.1.

(%i24) 

f(x,y):=y+sqrt(x^2+y^2)$

(%i25) 

h: 0.1$ x0: 0$ y0: 1$

(%i28) 

for i:1 thru 3 do
  ( x1: x0+h,
        k1: h*f(x0,y0),
        k2: h*f(x0+0.5*h, y0+0.5*k1),
        k3: h*f(x0+0.5*h, y0+0.5*k2),
        k4: h*f(x0+h, y0+k3),
        y1: y0+(1/6)*(k1+2*k2+2*k3+k4),
        x0: x1, y0: y1,
    display([i,x1,y1]) )$

[i,x1,y1]=[1,0.1,1.221551365567124] [i,x1,y1]=[2,0.2,1.492920208470706] [i,x1,y1]=[3,0.3,1.825519191636627]

(%i29) 


              

Ex. 3. y'=f(x,y)=x2+y2-3y(x+1), y(0)=2, h=0.05.

(%i29) 

f(x,y):=x^2+y^2-3*y*(x+1)$

(%i30) 

h: 0.05$ x0: 0$ y0: 2$

(%i33) 

for i:1 thru 3 do
  ( x1: x0+h,
        k1: h*f(x0,y0),
        k2: h*f(x0+0.5*h, y0+0.5*k1),
        k3: h*f(x0+0.5*h, y0+0.5*k2),
        k4: h*f(x0+h, y0+k3),
        y1: y0+(1/6)*(k1+2*k2+2*k3+k4),
        x0: x1, y0: y1,
    display([i,x1,y1]) )$

[i,x1,y1]=[1,0.05,1.890339767187235]

[i,x1,y1]=[2,0.1,1.763094323005745] [i,x1,y1]=[3,0.15,1.621677082133333]

(%i34) 


              

Ex. 4. y'=f(x,y)=(1+x)/(1-y2), y(2)=3, h=0.1.

(%i35) 

f(x,y):=(1+x)/(1-y^2)$

(%i36) 

h: 0.1$ x0: 2$ y0: 3$

(%i39) 

for i:1 thru 3 do
  ( x1: x0+h,
        k1: h*f(x0,y0),
        k2: h*f(x0+0.5*h, y0+0.5*k1),
        k3: h*f(x0+0.5*h, y0+0.5*k2),
        k4: h*f(x0+h, y0+k3),
        y1: y0+(1/6)*(k1+2*k2+2*k3+k4),
        x0: x1, y0: y1,
    display([i,x1,y1]) )$

[i,x1,y1]=[1,2.1,2.961316248057228]

[i,x1,y1]=[2,2.2,2.920128957785907] [i,x1,y1]=[3,2.3,2.876207301364791]

(%i40) 


              

Ex. 5. y'=f(x,y)=sin(xy)-x2y, y(1)=π, h=0.2.

(%i40) 

f(x,y):=sin(x*y)-x^2*y$

(%i41) 

h: 0.2$ x0: 1$ y0: 3.1415$

(%i44) 

for i:1 thru 3 do
  ( x1: x0+h,
        k1: h*f(x0,y0),
        k2: h*f(x0+0.5*h, y0+0.5*k1),
        k3: h*f(x0+0.5*h, y0+0.5*k2),
        k4: h*f(x0+h, y0+k3),
        y1: y0+(1/6)*(k1+2*k2+2*k3+k4),
        x0: x1, y0: y1,
    display([i,x1,y1]) )$

[i,x1,y1]=[1,1.2,2.475546873156627]

[i,x1,y1]=[2,1.4,1.825959686942205] [i,x1,y1]=[3,1.6,1.282767384068508]

(%i45) 


              

3. Exercise 13, p. 108. (Bonus point if you also do Euler's semilinear method)

(%i21) 

f(x,y):=7*exp(-3*x)-3*y$ yex(x):=exp(-3*x)*(7*x+6)$

(%i23) 

h: 0.1$ x0: 0$ y0: 6$

(%i26) 

for i:1 thru 10 do
  ( x1: x0+h, y1: y0+h*f(x0,y0), x0: x1, y0: y1, yE: yex(x1), err: abs((yE-y1)/yE),
    display([i,x1,y1,yE,err]) )$

[i,x1,y1,yE,err]=[1,0.1,4.9,4.96348207856751,0.01278982729516185]

[i,x1,y1,yE,err]=[2,0.2,3.948572754477203,4.061206107095796,0.02773396612937181] [i,x1,y1,yE,err]=[3,0.3,3.148169073399861,3.293214243898853,0.04404364847131009] [i,x1,y1,yE,err]=[4,0.4,2.488317113198322,2.650509064827378,0.06119275492446566] [i,x1,y1,yE,err]=[5,0.5,1.952657927577367,2.119736521410083,0.07882045345974094] [i,x1,y1,yE,err]=[6,0.6,1.523051661408057,1.686048659860183,0.09667395866596284] [i,x1,y1,yE,err]=[7,0.7,1.181845384740751,1.334775067957503,0.114573374112215] [i,x1,y1,yE,err]=[8,0.7999999999999999,0.9130112690956129,1.052328258157185,0.1323892882108299] [i,x1,y1,yE,err]=[9,0.8999999999999999,0.7026104556695179,0.8266278066989223,0.1500280416704813] [i,x1,y1,yE,err]=[10,0.9999999999999999,0.5388711778864874,0.6472318887822316,0.1674217738245641]

(%i27) 


              

(%i45) 

f(x,y):=7*exp(-3*x)-3*y$ yex(x):=exp(-3*x)*(7*x+6)$

(%i47) 

h: 0.05$ x0: 0$ y0: 6$

(%i50) 

for i:1 thru 20 do
  ( x1: x0+h, y1: y0+h*f(x0,y0), x0: x1, y0: y1, yE: yex(x1), err: abs((yE-y1)/yE),
    display([i,x1,y1,yE,err]) )$

[i,x1,y1,yE,err]=[1,0.05,5.45,5.465495650299117,0.002835177500922231]

[i,x1,y1,yE,err]=[2,0.1,4.93374779174877,4.96348207856751,0.005990610290935368] [i,x1,y1,yE,err]=[3,0.15,4.452972000225055,4.495278468933502,0.009411312113548191] [i,x1,y1,yE,err]=[4,0.2,4.008196053258918,4.061206107095796,0.01305278590620105] [i,x1,y1,yE,err]=[5,0.25,3.59905071790299,3.660840783742864,0.01687865424638865] [i,x1,y1,yE,err]=[6,0.3,3.224521403676897,3.293214243898853,0.02085890413878164] [i,x1,y1,yE,err]=[7,0.35,2.883142574034572,2.956973979989263,0.02496856802066262] [i,x1,y1,yE,err]=[8,0.4,2.57314940011829,2.650509064827379,0.02918671953839436] [i,x1,y1,yE,err]=[9,0.45,2.292594964269818,2.372048384909907,0.03349569981183482] [i,x1,y1,yE,err]=[10,0.4999999999999999,2.039439810855407,2.119736521410084,0.03788051474494664] [i,x1,y1,yE,err]=[11,0.5499999999999999,1.811619395279046,1.891691599914428,0.04232836083799484] [i,x1,y1,yE,err]=[12,0.6,1.607093954004454,1.686048659860183,0.04682824863564529] [i,x1,y1,yE,err]=[13,0.65,1.423884471781341,1.500991455237718,0.05137070113711299] [i,x1,y1,yE,err]=[14,0.7000000000000001,1.260097726069419,1.334775067957503,0.0559475103189904] [i,x1,y1,yE,err]=[15,0.7500000000000001,1.11394281704755,1.185741276320973,0.06055153911500327] [i,x1,y1,yE,err]=[16,0.8000000000000002,0.9837411230870701,1.052328258157185,0.0651765592517901] [i,x1,y1,yE,err]=[17,0.8500000000000002,0.8679312382753039,0.9330759087137797,0.06981711758936732] [i,x1,y1,yE,err]=[18,0.9000000000000002,0.765070135634412,0.8266278066989217,0.07446842528844488] [i,x1,y1,yE,err]=[19,0.9500000000000003,0.6738315447481625,0.731730659066706,0.07912626538348347] [i,x1,y1,yE,err]=[20,1.0,0.5930023253421316,0.6472318887822307,0.08378691529265074]

(%i51) 


              

(%i39) 

f(x,y):=7*exp(-3*x)-3*y$ yex(x):=exp(-3*x)*(7*x+6)$

(%i41) 

h: 0.025$ x0: 0$ y0: 6$

(%i44) 

for i:1 thru 40 do
  ( x1: x0+h, y1: y0+h*f(x0,y0), x0: x1, y0: y1, yE: yex(x1), err: abs((yE-y1)/yE),
    display([i,x1,y1,yE,err]) )$

[i,x1,y1,yE,err]=[1,0.025,5.725,5.728816028078814,0.666111123155433×10-3]

[i,x1,y1,yE,err]=[2,0.05,5.457980110107497,5.465495650299117,0.00137508849562596] [i,x1,y1,yE,err]=[3,0.07500000000000001,5.199255497723819,5.210318327404935,0.002123254086593534] [i,x1,y1,yE,err]=[4,0.1,4.949051673677424,4.96348207856751,0.00290731479668212] [i,x1,y1,yE,err]=[5,0.125,4.707515986770918,4.725113791687934,0.003724313464783166] [i,x1,y1,yE,err]=[6,0.15,4.474727911551519,4.495278468933502,0.004571587171741555] [i,x1,y1,yE,err]=[7,0.175,4.250708244718965,4.273987507550239,0.005446731603718906] [i,x1,y1,yE,err]=[8,0.2,4.035427315129236,4.061206107095797,0.006347570472111613] [i,x1,y1,yE,err]=[9,0.225,3.828812302810998,3.856859886102185,0.007272129172297274] [i,x1,y1,yE,err]=[10,0.25,3.630753753706494,3.660840783742864,0.008218612011202822] [i,x1,y1,yE,err]=[11,0.275,3.441111368908185,3.473012315284723,0.009185382452040789] [i,x1,y1,yE,err]=[12,0.3,3.259719139921437,3.293214243898853,0.01017094591992315] [i,x1,y1,yE,err]=[13,0.325,3.086389894881934,3.121266725735123,0.01117393478924004] [i,x1,y1,yE,err]=[14,0.35,2.920919314639342,2.956973979989262,0.01219309523651995] [i,x1,y1,yE,err]=[15,0.3750000000000001,2.763089472135843,2.800127530965766,0.0132272756938139] [i,x1,y1,yE,err]=[16,0.4000000000000001,2.612671943513366,2.650509064827378,0.01427541667980528] [i,x1,y1,yE,err]=[17,0.4250000000000001,2.469430534834499,2.50789293978713,0.01533654182059927] [i,x1,y1,yE,err]=[18,0.4500000000000001,2.333123664160658,2.372048384909907,0.01640974990091836] [i,x1,y1,yE,err]=[19,0.4750000000000001,2.20350643496164,2.242741419417789,0.0174942078103392] [i,x1,y1,yE,err]=[20,0.5000000000000001,2.080332433400976,2.119736521410082,0.01858914426916312] [i,x1,y1,yE,err]=[21,0.5250000000000001,1.963355278921878,2.002798072190151,0.01969384423520057] [i,x1,y1,yE,err]=[22,0.5500000000000002,1.852329954721939,1.891691599914428,0.02080764390679184] [i,x1,y1,yE,err]=[23,0.5750000000000002,1.747013942126425,1.786184844023306,0.02192992624920602] [i,x1,y1,yE,err]=[24,0.6000000000000002,1.647168180527201,1.686048659860182,0.02306011698156156] [i,x1,y1,yE,err]=[25,0.6250000000000002,1.552557872426438,1.591057781016132,0.02419768096989256] [i,x1,y1,yE,err]=[26,0.6500000000000002,1.462953151192318,1.500991455237717,0.02534211897920169] [i,x1,y1,yE,err]=[27,0.6750000000000003,1.378129627380534,1.415633968189478,0.02649296474349952] [i,x1,y1,yE,err]=[28,0.7000000000000003,1.297868827884864,1.334775067957502,0.02764978231808937] [i,x1,y1,yE,err]=[29,0.7250000000000003,1.221958540737771,1.258210301903708,0.02881216368288101] [i,x1,y1,yE,err]=[30,0.7500000000000003,1.150193077074822,1.185741276320973,0.02997972656939757] [i,x1,y1,yE,err]=[31,0.7750000000000004,1.082373460592537,1.117175848286674,0.03115211248749313] [i,x1,y1,yE,err]=[32,0.8000000000000004,1.018307553757082,1.052328258157184,0.03232898493068852] [i,x1,y1,yE,err]=[33,0.8250000000000004,0.9578101290509484,0.9910192102798284,0.03351002774154392] [i,x1,y1,yE,err]=[34,0.8500000000000004,0.9007028926671565,0.9330759087137792,0.03469494362066216] [i,x1,y1,yE,err]=[35,0.8750000000000004,0.8468144672673216,0.8783320540402981,0.03588345276481339] [i,x1,y1,yE,err]=[36,0.9000000000000005,0.7959803397032664,0.8266278066989211,0.03707529162132005] [i,x1,y1,yE,err]=[37,0.9250000000000005,0.7480427789549776,0.7778097217036752,0.03827021174728648] [i,x1,y1,yE,err]=[38,0.9500000000000005,0.7028507289540471,0.7317306590667058,0.03946797876351648] [i,x1,y1,yE,err]=[39,0.9750000000000005,0.6602596804355902,0.6882496737807628,0.0406683713940831] [i,x1,y1,yE,err]=[40,1.0,0.6201315254876487,0.6472318887822306,0.04187118058347113]

(%i45) 


              

The final values and relative errors from the three steps size are yh=0.1(1)=0.538871, εh=0.1=0.167,yh=0.05(1)=0.6059300, εh=0.05=0.083, yh=0.025(1)=0.6201315, εh=0.025=0.042. Notice that the method shows first-order convergence, reducing the interval size h by half reduces the relative error by half.

4. Exercises 13, p. 126.

(%i63) 

f(x,y):=exp(-3*x)*(1-4*x+3*x^2-4*x^3)-3*y$
yex(x):=-exp(-3*x)*(3-x+2*x^2-x^3+x^4)$

(%i65) 

h: 0.1$ x0: 0$ y0: -3$

(%i68) 

for i:1 thru 10 do
  ( x1: x0+h,
        k1: h*f(x0,y0),
        k2: h*f(x0+0.5*h, y0+0.5*k1),
        k3: h*f(x0+0.5*h, y0+0.5*k2),
        k4: h*f(x0+h, y0+k3),
        y1: y0+(1/6)*(k1+2*k2+2*k3+k4),
        x0: x1, y0: y1, yE: yex(x1), err: abs((yE-y1)/yE),
    display([i,x1,y1,yE,err]) )$

[i,x1,y1,yE,err]=[1,0.1,-2.162598010632905,-2.162522467992003,0.349326501899443×10-4]

[i,x1,y1,yE,err]=[2,0.2,-1.577172164112856,-1.577065117479794,0.678771167250355×10-4] [i,x1,y1,yE,err]=[3,0.3,-1.163350794222229,-1.163236453483828,0.982953535016681×10-4] [i,x1,y1,yE,err]=[4,0.4,-0.8680302936304252,-0.8679212410462013,1.256480185833875×10-4] [i,x1,y1,yE,err]=[5,0.5,-0.6555427389005404,-0.6554448454360126,1.49354236606591×10-4] [i,x1,y1,yE,err]=[6,0.6,-0.5015353521322574,-0.501450707309005,1.687998880421825×10-4] [i,x1,y1,yE,err]=[7,0.7,-0.3891276734724686,-0.3890563182025489,1.834060175384279×10-4] [i,x1,y1,yE,err]=[8,0.7999999999999999,-0.3064680184340518,-0.3064089590303197,1.927469872912144×10-4] [i,x1,y1,yE,err]=[9,0.8999999999999999,-0.2451534334639788,-0.2451052255131414,1.966826726620039×10-4] [i,x1,y1,yE,err]=[10,0.9999999999999999,-0.19918719755121,-0.1991482734714558,1.954527602757375×10-4]

(%i69) 


              

(%i69) 

f(x,y):=exp(-3*x)*(1-4*x+3*x^2-4*x^3)-3*y$
yex(x):=-exp(-3*x)*(3-x+2*x^2-x^3+x^4)$

(%i71) 

h: 0.05$ x0: 0$ y0: -3$

(%i74) 

for i:1 thru 20 do
  ( x1: x0+h,
        k1: h*f(x0,y0),
        k2: h*f(x0+0.5*h, y0+0.5*k1),
        k3: h*f(x0+0.5*h, y0+0.5*k2),
        k4: h*f(x0+h, y0+k3),
        y1: y0+(1/6)*(k1+2*k2+2*k3+k4),
        x0: x1, y0: y1, yE: yex(x1), err: abs((yE-y1)/yE),
    display([i,x1,y1,yE,err]) )$

[i,x1,y1,yE,err]=[1,0.05,-2.543292302947726,-2.543289861263845,0.960049390203239×10-6] [i,x1,y1,yE,err]=[2,0.1,-2.162526572313374,-2.162522467992003,1.897932359992188×10-6] [i,x1,y1,yE,err]=[3,0.15,-1.844109484541107,-1.844104303185068,0.280968708231894×10-5] [i,x1,y1,yE,err]=[4,0.2,-1.577070939293027,-1.577065117479794,0.369154904771009×10-5] [i,x1,y1,yE,err]=[5,0.25,-1.352524433802992,-1.352518293590483,0.453983693840401×10-5] [i,x1,y1,yE,err]=[6,0.3,-1.163242677781687,-1.163236453483828,0.535084491228065×10-5] [i,x1,y1,yE,err]=[7,0.35,-1.003323597091739,-1.003317456031253,0.61207551493789×10-5] [i,x1,y1,yE,err]=[8,0.4,-0.867927182473265,-0.8679212410462016,0.684558319620866×10-5] [i,x1,y1,yE,err]=[9,0.45,-0.7530678363014294,-0.7530621723953632,0.752116660984273×10-5] [i,x1,y1,yE,err]=[10,0.4999999999999999,-0.655450182857431,-0.6554448454360128,0.814320450505907×10-5] [i,x1,y1,yE,err]=[11,0.5499999999999999,-0.5723389177532403,-0.5723339342403538,0.870735175450322×10-5] [i,x1,y1,yE,err]=[12,0.6,-0.5014553253524618,-0.501450707309005,0.920936672249077×10-5] [i,x1,y1,yE,err]=[13,0.65,-0.4408947053237915,-0.4408904528006046,0.964530567606513×10-5] [i,x1,y1,yE,err]=[14,0.7000000000000001,-0.3890602133374718,-0.3890563182025488,1.001175084622411×10-5] [i,x1,y1,yE,err]=[15,0.7500000000000001,-0.3446096099591903,-0.3446060584307829,1.030605330501702×10-5] [i,x1,y1,yE,err]=[16,0.8000000000000002,-0.3064121844648638,-0.3064089590303196,1.05265673511536×10-5] [i,x1,y1,yE,err]=[17,0.8500000000000002,-0.2735137229442882,-0.2735108038042017,1.06728511118625×10-5] [i,x1,y1,yE,err]=[18,0.9000000000000002,-0.2451078593671625,-0.2451052255131413,1.074580933820204×10-5] [i,x1,y1,yE,err]=[19,0.9500000000000003,-0.2205125132319408,-0.2205101432419989,1.074775929595034×10-5] [i,x1,y1,yE,err]=[20,1.0,-0.1991504008547125,-0.1991482734714556,1.068240873886497×10-5]

(%i75) 


              

(%i75) 

f(x,y):=exp(-3*x)*(1-4*x+3*x^2-4*x^3)-3*y$
yex(x):=-exp(-3*x)*(3-x+2*x^2-x^3+x^4)$

(%i77) 

h: 0.025$ x0: 0$ y0: -3$

(%i80) 

for i:1 thru 40 do
  ( x1: x0+h,
        k1: h*f(x0,y0),
        k2: h*f(x0+0.5*h, y0+0.5*k1),
        k3: h*f(x0+0.5*h, y0+0.5*k2),
        k4: h*f(x0+h, y0+k3),
        y1: y0+(1/6)*(k1+2*k2+2*k3+k4),
        x0: x1, y0: y1, yE: yex(x1), err: abs((yE-y1)/yE),
    display([i,x1,y1,yE,err]) )$

[i,x1,y1,yE,err]=[1,0.025,-2.761182495226335,-2.761182417593181,2.811590919629436×10-8] [i,x1,y1,yE,err]=[2,0.05,-2.543290003551932,-2.543289861263845,0.559464687110792×10-7] [i,x1,y1,yE,err]=[3,0.07500000000000001,-2.344331834515073,-2.344331638854666,0.834610614576172×10-7] [i,x1,y1,yE,err]=[4,0.1,-2.162522707232189,-2.162522467992003,1.106301506085183×10-7] [i,x1,y1,yE,err]=[5,0.125,-1.996260174183906,-1.996259899847704,1.374250927939822×10-7] [i,x1,y1,yE,err]=[6,0.15,-1.844104605282431,-1.844104303185069,1.638179369449098×10-7] [i,x1,y1,yE,err]=[7,0.175,-1.704761441134865,-1.704761117603225,1.897812170633416×10-7] [i,x1,y1,yE,err]=[8,0.2,-1.577065457002586,-1.577065117479794,2.152877439567263×10-7] [i,x1,y1,yE,err]=[9,0.225,-1.45996680798114,-1.459966457136014,0.24031040189155×10-6] [i,x1,y1,yE,err]=[10,0.25,-1.352518651767027,-1.352518293590484,0.264821958424507×10-6] [i,x1,y1,yE,err]=[11,0.275,-1.253866168377135,-1.253865806267094,0.288794893296854×10-6] [i,x1,y1,yE,err]=[12,0.3,-1.163236816647704,-1.163236453483828,0.312201250700879×10-6] [i,x1,y1,yE,err]=[13,0.325,-1.079931685535221,-1.079931323744703,0.335012522896386×10-6] [i,x1,y1,yE,err]=[14,0.35,-1.003317814415813,-1.003317456031253,0.357199566394716×10-6] [i,x1,y1,yE,err]=[15,0.3750000000000001,-0.9328213709509302,-0.9328210176612347,0.37873256370667×10-6] [i,x1,y1,yE,err]=[16,0.4000000000000001,-0.867921587851058,-0.8679212410462014,0.399581022112287×10-6] [i,x1,y1,yE,err]=[17,0.4250000000000001,-0.8081453712008229,-0.8081450320111808,0.4197138243813×10-6] [i,x1,y1,yE,err]=[18,0.4500000000000001,-0.753062503064455,-0.753062172395363,0.439099325551113×10-6] [i,x1,y1,yE,err]=[19,0.4750000000000001,-0.7022813700101411,-0.7022810485722395,0.45770550448811×10-6] [i,x1,y1,yE,err]=[20,0.5000000000000001,-0.6554451571001412,-0.6554448454360123,0.475500159942172×10-6] [i,x1,y1,yE,err]=[21,0.5250000000000001,-0.6122284539023104,-0.6122281524098446,0.492451163155407×10-6] [i,x1,y1,yE,err]=[22,0.5500000000000002,-0.572334225287471,-0.5723339342403536,0.508526753341971×10-6] [i,x1,y1,yE,err]=[23,0.5750000000000002,-0.5354911052748305,-0.5354908248404925,0.523695878556236×10-6] [i,x1,y1,yE,err]=[24,0.6000000000000002,-0.5014509770536684,-0.5014507073090047,0.537928573606622×10-6] [i,x1,y1,yE,err]=[25,0.6250000000000002,-0.4699868066145442,-0.4699865475596645,0.551196371715218×10-6] [i,x1,y1,yE,err]=[26,0.6500000000000002,-0.4408907012303547,-0.4408904528006044,0.563472737385992×10-6] [i,x1,y1,yE,err]=[27,0.6750000000000003,-0.4139721673928694,-0.4139719294693267,0.574733516232095×10-6] [i,x1,y1,yE,err]=[28,0.7000000000000003,-0.3890565457839152,-0.3890563182025485,0.584957385469922×10-6] [i,x1,y1,yE,err]=[29,0.7250000000000003,-0.3659836034867012,-0.3659833860463469,0.594126298141839×10-6] [i,x1,y1,yE,err]=[30,0.7500000000000003,-0.3446062659614799,-0.3446060584307828,0.602225909991902×10-6] [i,x1,y1,yE,err]=[31,0.7750000000000004,-0.3247894733560878,-0.3247892754795301,0.609245971569487×10-6] [i,x1,y1,yE,err]=[32,0.8000000000000004,-0.3064091475271909,-0.3064089590303193,0.615180679287268×10-6] [i,x1,y1,yE,err]=[33,0.8250000000000004,-0.28935125774013,-0.2893510783340781,0.620028973079328×10-6] [i,x1,y1,yE,err]=[34,0.8500000000000004,-0.2735109744188106,-0.2735108038042016,0.623794770163831×10-6] [i,x1,y1,yE,err]=[35,0.8750000000000004,-0.2587919015540582,-0.2587917394243654,0.626487125123954×10-6] [i,x1,y1,yE,err]=[36,0.9000000000000005,-0.2451053794687126,-0.2451052255131411,0.628120315115568×10-6] [i,x1,y1,yE,err]=[37,0.9250000000000005,-0.2323698505977129,-0.232369704503664,0.628713838571457×10-6] [i,x1,y1,yE,err]=[38,0.9500000000000005,-0.2205102817868316,-0.2205101432419988,0.628292334928207×10-6] [i,x1,y1,yE,err]=[39,0.9750000000000005,-0.2094576373580673,-0.2094575060522114,0.626885416451722×10-6] [i,x1,y1,yE,err]=[40,1.0,-0.1991483978450135,-0.1991482734714556,0.624527422631212×10-6]

(%i81) 


              

The final values and relative errors from the three steps size are yh=0.1(1)=-0.199187, εh=0.1=1.93×10-4,yh=0.05(1)=-0.199148273, εh=0.05=1.068×10-5, yh=0.025(1)=-0.1991483978450, εh=0.025=6.24×10-6. Notice that the method shows high-order convergence (fourth), reducing the interval size h by half reduces the relative error by sixteen.