Page 1
Edurev123
5. Ordinary Differential Equation
5.1 Use Euler's method with step size ???
=?? .???? to compute the approximate value
of ?? (?? .?? ) correct upto few decimal places from the initial value problem
?? ?=?? (?? +?? )-?? ?? (?? )?=??
(2013 : 15 Marks)
Solution:
We use Euler's predictor equation
?? ?? =?? ?? -1
+h(?? 0
+(?? -1)h,?? ?? -1
)
to predict value at a point and then the equation
?? ?? ?? =?? ?? -1
+
h
2
[?? (?? ?? -1
,?? ?? -1
)+?? (?? ?? ,?? ?? ?? -1
)]
to refine it upto 5 decimal places
?? 0
=0,h=0.15,?? 0
=0
?? ?? '
=?? (?? +?? )-??
Mean Slope
(M.S.)
?? (?? )
=?? ?? -1
+h× M.S.
0 -2 - -0.30000
0.25 -2.02250 -2.01125 -0.30169
0.15 -2.02275 -2.01138 -0.30171
0.15 -2.02276 -2.01138 -0.30171
???? (0.15)=-0.30171
0.15 -2.02276 - -0.60512
0.30 -2.09154 -2.05715 -0.61028
0.30 -2.09308 -2.05792 -0.61039
Page 2
Edurev123
5. Ordinary Differential Equation
5.1 Use Euler's method with step size ???
=?? .???? to compute the approximate value
of ?? (?? .?? ) correct upto few decimal places from the initial value problem
?? ?=?? (?? +?? )-?? ?? (?? )?=??
(2013 : 15 Marks)
Solution:
We use Euler's predictor equation
?? ?? =?? ?? -1
+h(?? 0
+(?? -1)h,?? ?? -1
)
to predict value at a point and then the equation
?? ?? ?? =?? ?? -1
+
h
2
[?? (?? ?? -1
,?? ?? -1
)+?? (?? ?? ,?? ?? ?? -1
)]
to refine it upto 5 decimal places
?? 0
=0,h=0.15,?? 0
=0
?? ?? '
=?? (?? +?? )-??
Mean Slope
(M.S.)
?? (?? )
=?? ?? -1
+h× M.S.
0 -2 - -0.30000
0.25 -2.02250 -2.01125 -0.30169
0.15 -2.02275 -2.01138 -0.30171
0.15 -2.02276 -2.01138 -0.30171
???? (0.15)=-0.30171
0.15 -2.02276 - -0.60512
0.30 -2.09154 -2.05715 -0.61028
0.30 -2.09308 -2.05792 -0.61039
0.3 -2.09312 -2.05794 -0.61040
0.3 -2.09312 -2.05794 -0.61040
???? (0.3)=-0.61040
0.3 -2.09312 - -0.92437
0.45 -2.21345 -2.15329 -0.93339
0.45 -2.21753 -2.15532 -0.93370
0.45 -2.21766 -2.15539 -0.93371
0.45 -2.21767 -2.15539 -0.93371
???? (0.45)=-0.93371
0.45 -2.21767 - -1.26636
0.60 -2.39981 -2.30874 -1.28002
0.60 -2.40801 -2.31283 -1.28063
0.60 -2.40838 -2.31302 -1.28066
0.60 -2.40840 -2.31303 -1.28066
???? (0.6)=-1.28066
5.2 Use Runge-Kutta formula of fourth order to find the value of ?? at ?? =?? .?? ,
where
????
????
=v?? +?? , ?? (?? .?? )=?? .???? . Take the step length ?? =?? .?? .
(2014 : 20 Marks)
Solution:
Given that
????
????
=v?? +??
To find ?? (0.6; :
Page 3
Edurev123
5. Ordinary Differential Equation
5.1 Use Euler's method with step size ???
=?? .???? to compute the approximate value
of ?? (?? .?? ) correct upto few decimal places from the initial value problem
?? ?=?? (?? +?? )-?? ?? (?? )?=??
(2013 : 15 Marks)
Solution:
We use Euler's predictor equation
?? ?? =?? ?? -1
+h(?? 0
+(?? -1)h,?? ?? -1
)
to predict value at a point and then the equation
?? ?? ?? =?? ?? -1
+
h
2
[?? (?? ?? -1
,?? ?? -1
)+?? (?? ?? ,?? ?? ?? -1
)]
to refine it upto 5 decimal places
?? 0
=0,h=0.15,?? 0
=0
?? ?? '
=?? (?? +?? )-??
Mean Slope
(M.S.)
?? (?? )
=?? ?? -1
+h× M.S.
0 -2 - -0.30000
0.25 -2.02250 -2.01125 -0.30169
0.15 -2.02275 -2.01138 -0.30171
0.15 -2.02276 -2.01138 -0.30171
???? (0.15)=-0.30171
0.15 -2.02276 - -0.60512
0.30 -2.09154 -2.05715 -0.61028
0.30 -2.09308 -2.05792 -0.61039
0.3 -2.09312 -2.05794 -0.61040
0.3 -2.09312 -2.05794 -0.61040
???? (0.3)=-0.61040
0.3 -2.09312 - -0.92437
0.45 -2.21345 -2.15329 -0.93339
0.45 -2.21753 -2.15532 -0.93370
0.45 -2.21766 -2.15539 -0.93371
0.45 -2.21767 -2.15539 -0.93371
???? (0.45)=-0.93371
0.45 -2.21767 - -1.26636
0.60 -2.39981 -2.30874 -1.28002
0.60 -2.40801 -2.31283 -1.28063
0.60 -2.40838 -2.31302 -1.28066
0.60 -2.40840 -2.31303 -1.28066
???? (0.6)=-1.28066
5.2 Use Runge-Kutta formula of fourth order to find the value of ?? at ?? =?? .?? ,
where
????
????
=v?? +?? , ?? (?? .?? )=?? .???? . Take the step length ?? =?? .?? .
(2014 : 20 Marks)
Solution:
Given that
????
????
=v?? +??
To find ?? (0.6; :
Here
?? 0
=0.4,?? 0
=0.41,h=0.2
?? (?? 0
,?? 0
)=v0.81
???? 1
=h?? (?? 0
,?? 0
)=(0.2)v0.81=0.18
?? 2
=h?? (?? 0
+
h
2
,?? 0
+
?? 1
2
)=(0.2)?? (0.5,0.51)=0.2
?? 3
=h?? (?? 0
+
h
2
,?? 0
+
?? 2
2
)=(0.2)?? (0.5,0.51)=0.20099
?? 4
=h?? (?? 0
+h,?? 0
+?? 3
)=(0.2)?? (0.6,0.61099)=0.220099
?? =
1
6
(?? 1
+2?? 2
+2?? 3
+?? 4
)
=
1
6
[0.18+2(0.2)+2(0.20099)+0.220089]=
1
6
(1.202069982)
=0.2003449
?? 1
=?? (0.6)=?? 0
+?? =0.41+0.2003449=0.6103449
To find ?? (0.8) :
Here,
?? 1
?=0.6,?? 1
=0.6103449,h=0.2
?? 1
?=h?? (?? 1
,?? 1
)=(0.2)?? (0.6,0.6103449)=0.220031
?? 2
?=h?? (?? 1
+
h
2
,?? 1
+
?? 1
2
)=(0.2)?? (0.7,0.72036)=0.23836
?? 3
?=h?? (?? 1
+
h
2
,?? 1
+
?? 2
2
)=(0.2)?? (0.7,0.72952)=0.23913
?? 4
?=h?? (?? 1
+h,?? 1
+?? 3
)=(0.2)?? (0.8,0.85257)=0.257105
?? ?=
1
6
(?? 1
+2?? 2
+2?? 3
+?? 4
)=0.238686
?? 2
?=?? (0.8)=?? 1
+?? =0.6103449+0.238686
?=0.8490309
5.3 Solve the initial value problem
????
????
=?? (?? -?? ),?? (?? )=?? in the interval [?? ,?? .?? ]
using the Runge-Kutta fourth-order method with step size ?? =?? .?? .
(2015 : 15 Marks)
Solution:
Given :??????????????????????????????????????????
????
????
?=?? (?? -?? )=?? (?? ,?? )
Page 4
Edurev123
5. Ordinary Differential Equation
5.1 Use Euler's method with step size ???
=?? .???? to compute the approximate value
of ?? (?? .?? ) correct upto few decimal places from the initial value problem
?? ?=?? (?? +?? )-?? ?? (?? )?=??
(2013 : 15 Marks)
Solution:
We use Euler's predictor equation
?? ?? =?? ?? -1
+h(?? 0
+(?? -1)h,?? ?? -1
)
to predict value at a point and then the equation
?? ?? ?? =?? ?? -1
+
h
2
[?? (?? ?? -1
,?? ?? -1
)+?? (?? ?? ,?? ?? ?? -1
)]
to refine it upto 5 decimal places
?? 0
=0,h=0.15,?? 0
=0
?? ?? '
=?? (?? +?? )-??
Mean Slope
(M.S.)
?? (?? )
=?? ?? -1
+h× M.S.
0 -2 - -0.30000
0.25 -2.02250 -2.01125 -0.30169
0.15 -2.02275 -2.01138 -0.30171
0.15 -2.02276 -2.01138 -0.30171
???? (0.15)=-0.30171
0.15 -2.02276 - -0.60512
0.30 -2.09154 -2.05715 -0.61028
0.30 -2.09308 -2.05792 -0.61039
0.3 -2.09312 -2.05794 -0.61040
0.3 -2.09312 -2.05794 -0.61040
???? (0.3)=-0.61040
0.3 -2.09312 - -0.92437
0.45 -2.21345 -2.15329 -0.93339
0.45 -2.21753 -2.15532 -0.93370
0.45 -2.21766 -2.15539 -0.93371
0.45 -2.21767 -2.15539 -0.93371
???? (0.45)=-0.93371
0.45 -2.21767 - -1.26636
0.60 -2.39981 -2.30874 -1.28002
0.60 -2.40801 -2.31283 -1.28063
0.60 -2.40838 -2.31302 -1.28066
0.60 -2.40840 -2.31303 -1.28066
???? (0.6)=-1.28066
5.2 Use Runge-Kutta formula of fourth order to find the value of ?? at ?? =?? .?? ,
where
????
????
=v?? +?? , ?? (?? .?? )=?? .???? . Take the step length ?? =?? .?? .
(2014 : 20 Marks)
Solution:
Given that
????
????
=v?? +??
To find ?? (0.6; :
Here
?? 0
=0.4,?? 0
=0.41,h=0.2
?? (?? 0
,?? 0
)=v0.81
???? 1
=h?? (?? 0
,?? 0
)=(0.2)v0.81=0.18
?? 2
=h?? (?? 0
+
h
2
,?? 0
+
?? 1
2
)=(0.2)?? (0.5,0.51)=0.2
?? 3
=h?? (?? 0
+
h
2
,?? 0
+
?? 2
2
)=(0.2)?? (0.5,0.51)=0.20099
?? 4
=h?? (?? 0
+h,?? 0
+?? 3
)=(0.2)?? (0.6,0.61099)=0.220099
?? =
1
6
(?? 1
+2?? 2
+2?? 3
+?? 4
)
=
1
6
[0.18+2(0.2)+2(0.20099)+0.220089]=
1
6
(1.202069982)
=0.2003449
?? 1
=?? (0.6)=?? 0
+?? =0.41+0.2003449=0.6103449
To find ?? (0.8) :
Here,
?? 1
?=0.6,?? 1
=0.6103449,h=0.2
?? 1
?=h?? (?? 1
,?? 1
)=(0.2)?? (0.6,0.6103449)=0.220031
?? 2
?=h?? (?? 1
+
h
2
,?? 1
+
?? 1
2
)=(0.2)?? (0.7,0.72036)=0.23836
?? 3
?=h?? (?? 1
+
h
2
,?? 1
+
?? 2
2
)=(0.2)?? (0.7,0.72952)=0.23913
?? 4
?=h?? (?? 1
+h,?? 1
+?? 3
)=(0.2)?? (0.8,0.85257)=0.257105
?? ?=
1
6
(?? 1
+2?? 2
+2?? 3
+?? 4
)=0.238686
?? 2
?=?? (0.8)=?? 1
+?? =0.6103449+0.238686
?=0.8490309
5.3 Solve the initial value problem
????
????
=?? (?? -?? ),?? (?? )=?? in the interval [?? ,?? .?? ]
using the Runge-Kutta fourth-order method with step size ?? =?? .?? .
(2015 : 15 Marks)
Solution:
Given :??????????????????????????????????????????
????
????
?=?? (?? -?? )=?? (?? ,?? )
Step size??????????????????????????????????????????h=0.2
?? (2)?=3
Taking ?? 0
=?? (?? ),?? 0
=??
?? 1
?=h?? (?? 0
,?? 0
)=0.2?? (2,3)
?=0.4
?? 2
?=h?? (?? 0
+
h
2
,?? 0
+
?? 1
2
)=0.2?? (2.1,3.2)
?=0.462
?? 3
?=h?? (?? 0
+
h
2
,?? 0
+
?? 2
2
)=0.2?? (2.1.,3.231)
?=0.475
?? 4
?=h?? (?? 0
+h
1
?? 0
+?? 3
)=0.2?? (2.2,3.475)=0.561
?? ?=
1
6
(?? 1
+2?? 2
+2?? 3
+?? 4
)
?=
1
6
(0.4+0.462×2+0.475×2+0.561)
?=0.4725
?? 1
?=?? 0
+?? =?? (2.2)=?? (2)+?? =3+0.4725
?=3.4725( approx. )
Taking ?? 1
=?? (2.2)=3.4725,?? 1
=2.2
?? 1
=h?? (?? 1
,?? 1
)=0.2?? (2.2,3.4725)=0.5599
?? 2
=h?? (?? 1
+
h
2
,?? 1
+
?? 2
2
)=0.2?? (2.3,3.75245)=0.6681
?? 3
?=h?? (?? 1
+
h
2
,?? 1
+
?? 2
2
)=0.2?? (2.4,4.1655)=0.84744
?? ?=
1
6
(?? 1
+2?? 2
+2?? 3
+?? 4
)=0.6883
?? 2
?=?? (2.4)=?? 1
+?? =3.4725+0.6883=4.1608 (approx.)
???? (2.2)?=3.4725 (approx.)
?? (2.4)?=4.1608 (approx.)
5.4 Using Runge-Kutta method of fourth order, solve
????
????
=
?? ?? -?? ?? ?? ?? +?? ?? with ?? (?? )=?? at ?? =
?? .?? . Use four decimal places for calculation and step length 0.2 .
(2019 : 10 Marks)
Solution:
Page 5
Edurev123
5. Ordinary Differential Equation
5.1 Use Euler's method with step size ???
=?? .???? to compute the approximate value
of ?? (?? .?? ) correct upto few decimal places from the initial value problem
?? ?=?? (?? +?? )-?? ?? (?? )?=??
(2013 : 15 Marks)
Solution:
We use Euler's predictor equation
?? ?? =?? ?? -1
+h(?? 0
+(?? -1)h,?? ?? -1
)
to predict value at a point and then the equation
?? ?? ?? =?? ?? -1
+
h
2
[?? (?? ?? -1
,?? ?? -1
)+?? (?? ?? ,?? ?? ?? -1
)]
to refine it upto 5 decimal places
?? 0
=0,h=0.15,?? 0
=0
?? ?? '
=?? (?? +?? )-??
Mean Slope
(M.S.)
?? (?? )
=?? ?? -1
+h× M.S.
0 -2 - -0.30000
0.25 -2.02250 -2.01125 -0.30169
0.15 -2.02275 -2.01138 -0.30171
0.15 -2.02276 -2.01138 -0.30171
???? (0.15)=-0.30171
0.15 -2.02276 - -0.60512
0.30 -2.09154 -2.05715 -0.61028
0.30 -2.09308 -2.05792 -0.61039
0.3 -2.09312 -2.05794 -0.61040
0.3 -2.09312 -2.05794 -0.61040
???? (0.3)=-0.61040
0.3 -2.09312 - -0.92437
0.45 -2.21345 -2.15329 -0.93339
0.45 -2.21753 -2.15532 -0.93370
0.45 -2.21766 -2.15539 -0.93371
0.45 -2.21767 -2.15539 -0.93371
???? (0.45)=-0.93371
0.45 -2.21767 - -1.26636
0.60 -2.39981 -2.30874 -1.28002
0.60 -2.40801 -2.31283 -1.28063
0.60 -2.40838 -2.31302 -1.28066
0.60 -2.40840 -2.31303 -1.28066
???? (0.6)=-1.28066
5.2 Use Runge-Kutta formula of fourth order to find the value of ?? at ?? =?? .?? ,
where
????
????
=v?? +?? , ?? (?? .?? )=?? .???? . Take the step length ?? =?? .?? .
(2014 : 20 Marks)
Solution:
Given that
????
????
=v?? +??
To find ?? (0.6; :
Here
?? 0
=0.4,?? 0
=0.41,h=0.2
?? (?? 0
,?? 0
)=v0.81
???? 1
=h?? (?? 0
,?? 0
)=(0.2)v0.81=0.18
?? 2
=h?? (?? 0
+
h
2
,?? 0
+
?? 1
2
)=(0.2)?? (0.5,0.51)=0.2
?? 3
=h?? (?? 0
+
h
2
,?? 0
+
?? 2
2
)=(0.2)?? (0.5,0.51)=0.20099
?? 4
=h?? (?? 0
+h,?? 0
+?? 3
)=(0.2)?? (0.6,0.61099)=0.220099
?? =
1
6
(?? 1
+2?? 2
+2?? 3
+?? 4
)
=
1
6
[0.18+2(0.2)+2(0.20099)+0.220089]=
1
6
(1.202069982)
=0.2003449
?? 1
=?? (0.6)=?? 0
+?? =0.41+0.2003449=0.6103449
To find ?? (0.8) :
Here,
?? 1
?=0.6,?? 1
=0.6103449,h=0.2
?? 1
?=h?? (?? 1
,?? 1
)=(0.2)?? (0.6,0.6103449)=0.220031
?? 2
?=h?? (?? 1
+
h
2
,?? 1
+
?? 1
2
)=(0.2)?? (0.7,0.72036)=0.23836
?? 3
?=h?? (?? 1
+
h
2
,?? 1
+
?? 2
2
)=(0.2)?? (0.7,0.72952)=0.23913
?? 4
?=h?? (?? 1
+h,?? 1
+?? 3
)=(0.2)?? (0.8,0.85257)=0.257105
?? ?=
1
6
(?? 1
+2?? 2
+2?? 3
+?? 4
)=0.238686
?? 2
?=?? (0.8)=?? 1
+?? =0.6103449+0.238686
?=0.8490309
5.3 Solve the initial value problem
????
????
=?? (?? -?? ),?? (?? )=?? in the interval [?? ,?? .?? ]
using the Runge-Kutta fourth-order method with step size ?? =?? .?? .
(2015 : 15 Marks)
Solution:
Given :??????????????????????????????????????????
????
????
?=?? (?? -?? )=?? (?? ,?? )
Step size??????????????????????????????????????????h=0.2
?? (2)?=3
Taking ?? 0
=?? (?? ),?? 0
=??
?? 1
?=h?? (?? 0
,?? 0
)=0.2?? (2,3)
?=0.4
?? 2
?=h?? (?? 0
+
h
2
,?? 0
+
?? 1
2
)=0.2?? (2.1,3.2)
?=0.462
?? 3
?=h?? (?? 0
+
h
2
,?? 0
+
?? 2
2
)=0.2?? (2.1.,3.231)
?=0.475
?? 4
?=h?? (?? 0
+h
1
?? 0
+?? 3
)=0.2?? (2.2,3.475)=0.561
?? ?=
1
6
(?? 1
+2?? 2
+2?? 3
+?? 4
)
?=
1
6
(0.4+0.462×2+0.475×2+0.561)
?=0.4725
?? 1
?=?? 0
+?? =?? (2.2)=?? (2)+?? =3+0.4725
?=3.4725( approx. )
Taking ?? 1
=?? (2.2)=3.4725,?? 1
=2.2
?? 1
=h?? (?? 1
,?? 1
)=0.2?? (2.2,3.4725)=0.5599
?? 2
=h?? (?? 1
+
h
2
,?? 1
+
?? 2
2
)=0.2?? (2.3,3.75245)=0.6681
?? 3
?=h?? (?? 1
+
h
2
,?? 1
+
?? 2
2
)=0.2?? (2.4,4.1655)=0.84744
?? ?=
1
6
(?? 1
+2?? 2
+2?? 3
+?? 4
)=0.6883
?? 2
?=?? (2.4)=?? 1
+?? =3.4725+0.6883=4.1608 (approx.)
???? (2.2)?=3.4725 (approx.)
?? (2.4)?=4.1608 (approx.)
5.4 Using Runge-Kutta method of fourth order, solve
????
????
=
?? ?? -?? ?? ?? ?? +?? ?? with ?? (?? )=?? at ?? =
?? .?? . Use four decimal places for calculation and step length 0.2 .
(2019 : 10 Marks)
Solution:
Given:
?
?? '
=
?? 2
-?? 2
?? 2
+?? 2
at ?? =0,?? (0)=1,h=0.2,?? (0.2)=?
Using Runge-Kutta method for fourth order
?? (0.2)=?? (0)+?? ?? =
1
6
[?? 1
+?? 4
+2(?? 2
+?? 3
)]
?? 1
=h?? (?? 0
,?? 0
)
?? 2
=h?? (?? 0
+
h
2
,?? 0
+
?? 1
2
)
?? 3
=h?? (?? 0
+
h
2
,?? 0
+
?? 2
2
)
?? 4
=h?? (?? 0
+h
1
,?? 0
+?? 3
)
?? 1
=0.2?? (0,1)=0.2×1=0.2
?? 2
=0.2?? (0.1,1.1)=0.2×0.98361=0.19672
?? 3
=0.2?? (0.1,1.09836)=0.2×0.98356=0.19672
?? 4
=0.2?? (0.2,1.19671)=0.2×0.94566=0.18913
??
?? (0.2)=1+
1
6
{(0.2+0.18913+2(0.19672+0.19671)}
?? (0.2)=1+
1
6
(0.38913+0.78686)
?? (0.2)=1+
1
6
(1.17599)
?? (0.2)=1+0.195998
?? (0.2)=1.960( Required solution )
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