department of applied science & humanities (mathematics

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Government Engineering College, Nawada Department of Applied Science & Humanities (Mathematics) Tutorial Sheet-I Session : 2019-20(Even Sem.) Semester : II Course/ Branch : B. Tech./ME Paper Name : Mathematics-II (102202) Module : 2 Topic Covered : FIRST ORDER ORDINARY DIFFERENTIAL EQUATIONS Name of Faculty: Dr. Rajnesh Kumar Note: Following are the problems which are required to be done by the students for an overall understanding of the topics. 1. Find theorder and degree of the following differential equations. State also whether they are linear or non-linear (i)1+ dy dx 2 5/2 = d 2 y dx 2 (ii) d 2 y dx 2 +5 dy dx + 6y = 0 (iii) yโ€ฒโ€ฒ + xyyโ€ฒ + 3y = 5x (iv) (yโ€ฒ) 2 +3xyโ€ฒ +y=0 (v) yโ€ฒ = siny 2. Eliminate the arbitrary constants and obtain the following differential equations satisfied by it (i) y = a cosฮธx + b sinฮธx, ฮธ: fixed constant (ii) y = c cos(pt โˆ’ a), p: fixed constant (iii) x 2 +y 2 =a 2 (iv) y = 2cx โˆ’ c 2 (v) x 2 +y 2 โˆ’ 2ay = 0. 3. Reduce to separable form and solve the following differential equations (i) (xyโ€ฒ-y) cos(y/x) +x=0 (ii) xyโ€ฒ =e โˆ’xy โˆ’ y (iii) dy dx =e x โˆ’y +x 2 e โˆ’y (iv) x 2 (1 โˆ’ y)dy + y 2 (1 + x)dx = 0 (v) sec 2 x tany dx + sec 2 y tanx dy = 0 (vi) yโ€ฒ = cos(x + y) + sin(x + y) (vii) sin 3 x dy dx = siny. 4. Solve the following differential equations (i) dy dx = x 2 y x 3+ y 3 (ii) (x 2 โˆ’ y 2 )dx โˆ’ xy dy = 0 (iii) (1 + e x/y )+e x/y (1 โˆ’ x/y)dy = 0 (iv)( x 2 + 4y 2 + xy)dx โˆ’ x 2 dy = 0 (v) (3xy + y 2 ) dx + (x 2 + xy)dy = 0. 5. Solve the following differential equations(i) dy dx = x โˆ’y โˆ’2 2x โˆ’2y โˆ’3 (ii) dy dx = 2x โˆ’6y+7 x โˆ’3y+4 (iii) dy dx = x+2y โˆ’3 2x+y โˆ’3 . 6. Solve the following differential equations (i)(x 2 + 1) dy dx + 2xy = 4x 2 (ii) x dy dx +y=y 2 log x(iii) x dy dx = 2y + x 4 + 6x 2 + 2x (iv) (1 + y 2 )dx = (tan โˆ’1 y โˆ’ x)dy (v) (x + 1) dy dx โˆ’ y=e 3x (x + 1) 2 (vi) (1 + x 2 ) dy dx +y=e tan โˆ’1 x 7. Solve the following differential equations(i) (y 2 e xy 2 + 4x 3 )dx + (2xye xy 2 โˆ’ 3y 2 )dy = 0 (ii)(2x 3 + 3y 2 x โˆ’ 7x)dx + (3x 2 y + 2y 3 โˆ’ 8y)dy = 0 (iii)(x 2 y โˆ’ 2xy 2 )dx โˆ’ (x 3 โˆ’ 3x 2 y)dy = 0 (iv) (1 โˆ’ xy)ydx โˆ’ x(1 + xy)dy = 0 (v)(xy 3 + y)dx + 2(x 2 y 2 +x+y 4 )dy = 0 (vi) y(xy + 2x 2 y 2 )dx + x(xy โˆ’ x 2 y 2 )dy = 0 (vii) (cosy + ycosx)dx + (sinx โˆ’ x siny)dy = 0. 8. Solve: (i) x dy dx +y=x 3 y 6 (ii) yโ€ฒ + 4xy + xy 3 =0 (iii) yโ€ฒ โˆ’ y=y 2 (sinx + cosx). 9. Solve : (i) dy dx 2 โˆ’ 5 dy dx +6=0 (ii) dy dx 2 + 2x dy dx โˆ’ 3x 2 =0 (iii) x 4 dy dx 2 โˆ’ x dy dx โˆ’ y=0.

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Government Engineering College, Nawada

Department of Applied Science & Humanities (Mathematics)

Tutorial Sheet-I Session : 2019-20(Even Sem.) Semester : II

Course/

Branch

: B. Tech./ME Paper Name : Mathematics-II

(102202)

Module : 2 Topic Covered : FIRST ORDER ORDINARY

DIFFERENTIAL EQUATIONS

Name of Faculty: Dr. Rajnesh Kumar

Note: Following are the problems which are required to be done by the students for an overall

understanding of the topics.

1. Find theorder and degree of the following differential equations. State also whether they are linear

or non-linear (i) 1 + dy

dx

2

5/2

=d2y

dx2 (ii) d2y

dx2 + 5dy

dx+ 6y = 0 (iii) yโ€ฒโ€ฒ + xyyโ€ฒ + 3y = 5x (iv)

(yโ€ฒ)2 + 3xyโ€ฒ + y = 0 (v) yโ€ฒ = siny

2. Eliminate the arbitrary constants and obtain the following differential equations satisfied by it

(i) y = a cosฮธx + b sinฮธx, ฮธ: fixed constant (ii) y = c cos(pt โˆ’ a), p: fixed constant (iii)

x2 + y2 = a2 (iv) y = 2cx โˆ’ c2(v) x2 + y2 โˆ’ 2ay = 0.

3. Reduce to separable form and solve the following differential equations (i) (xyโ€ฒ-y) cos(y/x) +x=0

(ii) xyโ€ฒ = eโˆ’xy โˆ’ y (iii) dy

dx= exโˆ’y + x2eโˆ’y (iv) x2(1 โˆ’ y)dy + y2(1 + x)dx = 0 (v)

sec2x tany dx + sec2y tanx dy = 0 (vi) yโ€ฒ = cos(x + y) + sin(x + y) (vii) sin3xdy

dx= siny.

4. Solve the following differential equations (i)dy

dx=

x2y

x3+y3 (ii) (x2 โˆ’ y2)dx โˆ’ xy dy = 0 (iii)

(1 + ex/y) + ex/y(1 โˆ’ x/y)dy = 0 (iv)( x2 + 4y2 + xy)dx โˆ’ x2dy = 0 (v) (3xy + y2) dx +

(x2 + xy)dy = 0.

5. Solve the following differential equations(i)dy

dx=

xโˆ’yโˆ’2

2xโˆ’2yโˆ’3 (ii)

dy

dx=

2xโˆ’6y+7

xโˆ’3y+4 (iii)

dy

dx=

x+2yโˆ’3

2x+yโˆ’3 .

6. Solve the following differential equations

(i)(x2 + 1)dy

dx+ 2xy = 4x2 (ii) x

dy

dx+ y = y2 log x(iii) x

dy

dx= 2y + x4 + 6x2 + 2x (iv) (1 +

y2)dx = (tanโˆ’1y โˆ’ x)dy (v) (x + 1)dy

dxโˆ’ y = e3x(x + 1)2(vi) (1 + x2)

dy

dx+ y = etan โˆ’1x

7. Solve the following differential equations(i) (y2exy 2+ 4x3)dx + (2xyexy2

โˆ’ 3y2)dy = 0

(ii)(2x3 + 3y2x โˆ’ 7x)dx + (3x2y + 2y3 โˆ’ 8y)dy = 0 (iii)(x2y โˆ’ 2xy2)dx โˆ’ (x3 โˆ’ 3x2y)dy =

0 (iv) (1 โˆ’ xy)ydx โˆ’ x(1 + xy)dy = 0 (v)(xy3 + y)dx + 2(x2y2 + x + y4)dy = 0 (vi) y(xy +

2x2y2)dx + x(xy โˆ’ x2y2)dy = 0 (vii) (cosy + ycosx)dx + (sinx โˆ’ x siny)dy = 0.

8. Solve: (i) xdy

dx+ y = x3y6 (ii) yโ€ฒ + 4xy + xy3 = 0 (iii) yโ€ฒ โˆ’ y = y2(sinx + cosx).

9. Solve : (i) dy

dx

2โˆ’ 5

dy

dx+ 6 = 0 (ii)

dy

dx

2+ 2x

dy

dxโˆ’ 3x2 = 0 (iii) x4

dy

dx

2โˆ’ x

dy

dxโˆ’ y = 0.

10. Solve: (i) y = 2px + y2p3 (ii) y = xyโ€ฒ + (yโ€ฒ)2 (iii) y = xyโ€ฒ โˆ’ e2yโ€ฒ (iv) y = xyโ€ฒ โˆ’1

yโ€ฒ .

11. Find the orthogonal trajectories of the hyperbolas x2 โˆ’ y2 = c.

12. Find the orthogonal trajectories of the family of circles passing through the points (0, 2) and (0, -

2).

13. Find the orthogonal trajectories of the following family of curves (i)r = c(1 + cosฮธ) (ii) r2 =

c sin(2ฮธ).

14. A body is heated to 100โ„ƒ and placed in air at 20โ„ƒ . After one hour its temperature is 60โ„ƒ. How

much additional time is required for it to cool to 30โ„ƒ.

15. In a radioactive decay, initially 50 mg of the material is present and after two hours, the material

has lost 10% of its original mass. Find the mass at any time t and the half-life of the material.

16. A particle falls down from rest in the air whose resistance is prepositional to the square of the

velocity. Find the velocity as a function of x.

Text / Reference Books:

1. Peter V. O` Neil, A text book of Engineering Mathematics, Thomson (Cengage Learning), 2nd

Edition, 2010.

2. B.S.Grewal, Advanced Engineering Mathematics, Khanna Publishars, 40th

Edition, 2010.

3. E. Kreyszig, โ€œAdvanced Engineering Mathematicsโ€, John Wiley and Sons, New York, 2005.

4. B.V. Ramanna, โ€œHigher Engineering Mathematicsโ€, Tata Mcgraw Hill Publishing Company Ltd.,

2008.

5. R.K. Jain and S.R.K. Iyengar, โ€œAdvanced Engineering Mathematicsโ€, Narosa Publishing House,

2008.

Government Engineering College, Nawada

Department of Applied Science & Humanities (Mathematics)

Tutorial Sheet-II Session : 2019-20(Even Sem.) Semester : II

Course/

Branch

: B. Tech./ME Paper Name : Mathematics-II

(102202)

Module : 3 Topic Covered : ORDINARY DIFFERENTIAL

EQUATIONS OF HIGHER

ORDERS Name of Faculty: Dr. Rajnesh Kumar

Note: Following are the problems which are required to be done by the students for an overall

understanding of the topics.

1. Examine whether the following functions are linearly independent (i) 1, ๐‘๐‘œ๐‘ ๐‘ฅ, ๐‘ ๐‘–๐‘›๐‘ฅ (ii)

๐‘™๐‘›๐‘ฅ, ๐‘™๐‘› ๐‘ฅ2, ๐‘™๐‘› ๐‘ฅ3 (iii) ๐‘’โˆ’๐‘ฅ , ๐‘ ๐‘–๐‘›๐‘ฅ, ๐‘๐‘œ๐‘ ๐‘ฅ (iv) ๐‘ฅ, ๐‘ฅ2 , ๐‘ฅ3 (v) ๐‘’๐‘ฅ , ๐‘’2๐‘ฅ , ๐‘’3๐‘ฅ .

2. Find a general solution of the following differential equations: (i) ๐‘ฆโ€ฒโ€ฒ โˆ’ 4๐‘ฆ = 0 (ii) ๐‘ฆโ€ฒโ€ฒ โˆ’ ๐‘ฆโ€ฒ โˆ’

2๐‘ฆ = 0 (iii) ๐‘ฆโ€ฒโ€ฒ + ๐‘ฆโ€ฒ โˆ’ 2๐‘ฆ = 0 (iv) ๐‘ฆโ€ฒโ€ฒ โˆ’ 4๐‘ฆโ€ฒ โˆ’ 12๐‘ฆ = 0 (v) ๐‘ฆโ€ฒโ€ฒ + 9๐‘ฆโ€ฒ = 0 (vi) 9๐‘ฆโ€ฒโ€ฒ โˆ’ 12๐‘ฆโ€ฒ +

4๐‘ฆ = 0 (vii) ๐‘ฆโ€ฒโ€ฒ โˆ’ ๐‘ฆโ€ฒ โˆ’ 6๐‘ฆ = 0 (viii) 4๐‘ฆโ€ฒโ€ฒ + 4๐‘ฆโ€ฒ + ๐‘ฆ = 0 (ix) ๐‘ฆโ€ฒโ€ฒโ€ฒ โˆ’ ๐‘ฆโ€ฒโ€ฒ โˆ’ 5๐‘ฆโ€ฒ + 6๐‘ฆ = 0 (x)

8๐‘ฆโ€ฒโ€ฒโ€ฒ โˆ’ 12๐‘ฆโ€ฒโ€ฒ + 6๐‘ฆโ€ฒ โˆ’ ๐‘ฆ = 0 (xi) ๐‘ฆ๐‘–๐‘ฃ โˆ’ ๐‘Ž2๐‘ฆ = 0 (xii) ๐‘ฆ๐‘–๐‘ฃ + 32๐‘ฆโ€ฒโ€ฒ + 256๐‘ฆ = 0.

3. Solve the following differential equations: (i) ๐‘ฆโ€ฒโ€ฒโ€ฒ + ๐‘ฆ = ๐‘’๐‘ฅ + 2๐‘’โˆ’๐‘ฅ (ii) ๐‘ฆโ€ฒโ€ฒ โˆ’ 4๐‘ฆโ€ฒ + 3๐‘ฆ =

๐‘ ๐‘–๐‘›3๐‘ฅ ๐‘๐‘œ๐‘ 2๐‘ฅ(iii) ๐‘ฆโ€ฒโ€ฒ โˆ’ 4๐‘ฆโ€ฒ + 4๐‘ฆ = ๐‘’๐‘ฅ + ๐‘ ๐‘–๐‘›2๐‘ฅ (iv) ๐‘ฆโ€ฒโ€ฒ + 4๐‘ฆ = ๐‘๐‘œ๐‘ ๐‘ฅ ๐‘๐‘œ๐‘ 3๐‘ฅ (v) ๐‘ฆโ€ฒโ€ฒ โˆ’ 4๐‘ฆ = ๐‘ฅ2

(vi) ๐‘ฆโ€ฒโ€ฒ โˆ’ 2๐‘ฆโ€ฒ + 3๐‘ฆ = ๐‘๐‘œ๐‘ ๐‘ฅ + ๐‘ฅ2 (vii) ๐‘ฆโ€ฒโ€ฒ โˆ’ 4๐‘ฆโ€ฒ + 4๐‘ฆ = ๐‘ฅ2 + ๐‘’๐‘ฅ + ๐‘๐‘œ๐‘ 2๐‘ฅ (viii) ๐‘ฆโ€ฒโ€ฒ โˆ’ 2๐‘ฆโ€ฒ + ๐‘ฆ =

๐‘ฅ๐‘’๐‘ฅ๐‘ ๐‘–๐‘›๐‘ฅ (ix) ๐‘ฆโ€ฒโ€ฒ โˆ’ 3๐‘ฆโ€ฒ + 2๐‘ฆ = ๐‘ ๐‘–๐‘›2๐‘ฅ + ๐‘ฅ๐‘’๐‘ฅ .

4. Solve by method of variation of parameters: (i) ๐‘ฆโ€ฒโ€ฒ + ๐‘Ž2๐‘ฆ = ๐‘ ๐‘’๐‘ ๐‘Ž๐‘ฅ (ii) ๐‘ฅ2๐‘ฆโ€ฒโ€ฒ + ๐‘ฅ๐‘ฆโ€ฒ โˆ’ ๐‘ฆ = ๐‘ฅ2๐‘’๐‘ฅ

(iii) ๐‘ฅ2๐‘ฆโ€ฒโ€ฒ โˆ’ 4๐‘ฅ๐‘ฆโ€ฒ + 6๐‘ฆ = ๐‘ ๐‘–๐‘›(๐‘™๐‘œ๐‘” ๐‘ฅ) (iv) ๐‘ฆโ€ฒโ€ฒ + 4๐‘ฆ = ๐‘๐‘œ๐‘  ๐‘ฅ (v) ๐‘ฆโ€ฒโ€ฒ + ๐‘Ž2๐‘ฆ = ๐‘๐‘œ๐‘ ๐‘’๐‘ax (vi)

๐‘ฆโ€ฒโ€ฒ + ๐‘ฆ = ๐‘ก๐‘Ž๐‘› ๐‘ฅ (vii) ๐‘ฆโ€ฒโ€ฒ + 6๐‘ฆโ€ฒ + 9๐‘ฆ =๐‘’โˆ’3๐‘ฅ

๐‘ฅ (viii) ๐‘ฆโ€ฒโ€ฒ + 4๐‘ฆโ€ฒ + 4๐‘ฆ = ๐‘’โˆ’2๐‘ฅ๐‘ ๐‘–๐‘› ๐‘ฅ (ix) ๐‘ฆโ€ฒโ€ฒ โˆ’ ๐‘ฆ =

2

1+๐‘’๐‘ฅ

(x) ๐‘ฅ2๐‘ฆโ€ฒโ€ฒ + ๐‘ฅ๐‘ฆโ€ฒ โˆ’ ๐‘ฆ = ๐‘ฅ2๐‘ฆ (xi) ๐‘ฅ2๐‘ฆโ€ฒโ€ฒ + 3๐‘ฅ๐‘ฆโ€ฒ + ๐‘ฆ =1

(1โˆ’๐‘ฅ)2.

5. Solve the following differential equations:(i) ๐‘ฅ๐‘ฆโ€ฒโ€ฒ โˆ’ (2๐‘ฅ โˆ’ 1)๐‘ฆโ€ฒ + (๐‘ฅ โˆ’ 1)๐‘ฆ = 0 (ii) (1 โˆ’

๐‘ฅ2)๐‘ฆโ€ฒโ€ฒ + ๐‘ฅ๐‘ฆโ€ฒ โˆ’ ๐‘ฆ = ๐‘ฅ (1 โˆ’ ๐‘ฅ2 )3/2(iii) ๐‘ฆโ€ฒโ€ฒ โˆ’ ๐‘๐‘œ๐‘ก ๐‘ฅ ๐‘ฆโ€ฒ โˆ’ (1 โˆ’ ๐‘๐‘œ๐‘ก ๐‘ฅ) ๐‘ฆ = ๐‘’๐‘ฅ๐‘ ๐‘–๐‘› ๐‘ฅ .

6. Solve: (i) ๐‘ฆโ€ฒโ€ฒ โˆ’ 2๐‘ก๐‘Ž๐‘› ๐‘ฅ ๐‘ฆโ€ฒ + ๐‘ฆ = 0 (ii) ๐‘ฆโ€ฒโ€ฒ โˆ’ 4๐‘ฅ๐‘ฆโ€ฒ + (4๐‘ฅ2 โˆ’ 1)๐‘ฆ = โˆ’3๐‘’๐‘ฅ2๐‘ ๐‘–๐‘› 2๐‘ฅ (iii) ๐‘ฅ2๐‘ฆโ€ฒโ€ฒ โˆ’

2(๐‘ฅ + ๐‘ฅ2)๐‘ฆโ€ฒ + (๐‘ฅ2 + 2๐‘ฅ + 2)๐‘ฆ = 0 (iv) (๐‘๐‘œ๐‘  ๐‘ฅ) ๐‘ฆโ€ฒโ€ฒ + (๐‘ ๐‘–๐‘› ๐‘ฅ) ๐‘ฆโ€ฒ โˆ’ 2(๐‘๐‘œ๐‘ 3๐‘ฅ)๐‘ฆ = 2๐‘๐‘œ๐‘ 5๐‘ฅ .

7. Solve: (i) ๐‘ฅ3๐‘ฆโ€ฒโ€ฒโ€ฒ + 2๐‘ฅ2๐‘ฆโ€ฒโ€ฒ + 2๐‘ฆ = ๐‘ฅ +1

๐‘ฅ (ii) ๐‘ฅ2๐‘ฆโ€ฒโ€ฒ โˆ’ 5๐‘ฅ๐‘ฆโ€ฒ + 3๐‘ฆ = ๐‘™๐‘› ๐‘ฅ (iii) (๐‘ฅ + 1)2๐‘ฆโ€ฒโ€ฒ + (๐‘ฅ +

1)๐‘ฆโ€ฒ + ๐‘ฆ = 4๐‘๐‘œ๐‘ (๐‘™๐‘œ๐‘”(1 + ๐‘ฅ)) (iv) (2๐‘ฅ + 5)2๐‘ฆโ€ฒโ€ฒ + 6(2๐‘ฅ + 5)๐‘ฆโ€ฒ + 8๐‘ฆ = ๐‘ฅ .

8. Find the regular and singular points of the differential equations (i) (1 โˆ’ ๐‘ฅ2)๐‘ฆโ€ฒโ€ฒ โˆ’ 2๐‘ฅ๐‘ฆโ€ฒ + ๐‘›(๐‘› +

1)๐‘ฆ = 0 (ii) ๐‘ฅ2๐‘ฆโ€ฒโ€ฒ + ๐‘Ž๐‘ฅ๐‘ฆโ€ฒ + ๐‘๐‘ฆ = 0.

9. Classify the singular points of the following equations (i) ๐‘ฅ2๐‘ฆโ€ฒโ€ฒ + (๐‘ ๐‘–๐‘› ๐‘ฅ)๐‘ฆโ€ฒ + (๐‘๐‘œ๐‘  ๐‘ฅ)๐‘ฆ = 0 (ii)

๐‘ฅ3(๐‘ฅ2 โˆ’ 1)๐‘ฆโ€ฒโ€ฒ โˆ’ ๐‘ฅ(๐‘ฅ + 1)๐‘ฆโ€ฒ โˆ’ (๐‘ฅ โˆ’ 1)๐‘ฆ = 0 (iii) ๐‘ฅ2๐‘ฆโ€ฒโ€ฒ + 2๐‘ฅ๐‘ฆโ€ฒ + (๐‘ฅ2 โˆ’ ๐‘›2)๐‘ฆ = 0.

10. Find the power series solution about ๐‘ฅ = 0, of the differential equation (i) ๐‘ฆโ€ฒโ€ฒ โˆ’ 2๐‘ฆ = 0 (ii)

(1 โˆ’ ๐‘ฅ2)๐‘ฆโ€ฒโ€ฒ โˆ’ 2๐‘ฅ๐‘ฆโ€ฒ + 2๐‘ฆ = 0.

11. Find the power series solution about ๐‘ฅ = 2 of the equation ๐‘ฆโ€ฒโ€ฒ + (๐‘ฅ โˆ’ 1)๐‘ฆโ€ฒ + ๐‘ฆ = 0.

12. Find the series solutions of the following differential equations by the Frobenious method: (i) )

๐‘ฅ2๐‘ฆโ€ฒโ€ฒ + 2๐‘ฅ๐‘ฆโ€ฒ + (๐‘ฅ2 โˆ’ ๐‘›2)๐‘ฆ = 0 (ii) 9๐‘ฅ(1 + ๐‘ฅ)๐‘ฆโ€ฒโ€ฒ โˆ’ 6๐‘ฆโ€ฒ + 2๐‘ฆ = 0 (iii) (1 โˆ’ ๐‘ฅ2)๐‘ฆโ€ฒโ€ฒ โˆ’ 2๐‘ฅ๐‘ฆโ€ฒ +

6๐‘ฆ = 0.

13. Find the series solutions about the indicated point of the following differential equations by the

Frobenious method: (i) 2(1 โˆ’ ๐‘ฅ)๐‘ฆโ€ฒโ€ฒ โˆ’ ๐‘ฅ๐‘ฆโ€ฒ + ๐‘ฆ = 0, x=1 (ii) ๐‘ฅ(๐‘ฅ โˆ’ 2)๐‘ฆโ€ฒโ€ฒ + 4๐‘ฆโ€ฒ + 3๐‘ฆ = 0, ๐‘ฅ = 2.

14. Express ๐‘ƒ(๐‘ฅ) = 3๐‘ƒ3(๐‘ฅ) + 2๐‘ƒ2(๐‘ฅ) + 4๐‘ƒ1(๐‘ฅ) + 5๐‘ƒ0(๐‘ฅ) as polynomial in ๐‘ฅ, where ๐‘ƒ๐‘š (๐‘ฅ) is the

Legendre polynomial of order ๐‘š.

15. Express ๐‘“(๐‘ฅ) = ๐‘ฅ4 + 2๐‘ฅ3 โˆ’ 6๐‘ฅ2 + 5๐‘ฅ โˆ’ 3 in the terms of Legendre polynomials.

16. Show that (i) ๐‘ƒ๐‘›(1) = 1 (ii) ๐‘ƒ๐‘›(โˆ’๐‘ฅ) = (โˆ’1)๐‘› ) ๐‘ƒ๐‘›(๐‘ฅ) (iii) ๐‘ƒโ€ฒ๐‘›(1) = ๐‘›(๐‘› + 1)/2 (iv)

๐‘ƒ๐‘›(๐‘ฅ) ๐‘‘๐‘ฅ = 01

โˆ’1 (v) ) ๐‘ƒ๐‘›

2(๐‘ฅ) ๐‘‘๐‘ฅ =2

2๐‘›+1

1

โˆ’1.

17. Show that ๐ฝ๐‘›(๐‘ฅ) is a even function for n even and an odd function for ๐‘› odd where n is an integer.

18. Prove that (i) ๐ฝ1/2(๐‘ฅ) = 2

๐œ‹๐‘ฅ๐‘ ๐‘–๐‘› ๐‘ฅ (ii) ๐ฝโˆ’1/2(๐‘ฅ) =

2

๐œ‹๐‘ฅ๐‘๐‘œ๐‘  ๐‘ฅ (iii) ๐ฝ3(๐‘ฅ) =

8

๐‘ฅ2 โˆ’ 1 ๐ฝ1(๐‘ฅ) โˆ’

4

๐‘ฅ๐ฝ0(๐‘ฅ) (iv) ๐ฝ5/2(๐‘ฅ) =

2

๐œ‹๐‘ฅ

1

๐‘ฅ2 (3 โˆ’ ๐‘ฅ2)๐‘ ๐‘–๐‘› ๐‘ฅ โˆ’3

๐‘ฅ๐‘๐‘œ๐‘  ๐‘ฅ (v) ๐ฝโˆ’5/2(๐‘ฅ) =

2

๐œ‹๐‘ฅ

1

๐‘ฅ2 (3 โˆ’ ๐‘ฅ2)๐‘๐‘œ๐‘  ๐‘ฅ +

3

๐‘ฅ๐‘ ๐‘–๐‘› ๐‘ฅ .

Text / Reference Books:

1. Peter V. O` Neil, A text book of Engineering Mathematics, Thomson (Cengage Learning), 2nd

Edition, 2010.

2. B.S.Grewal, Advanced Engineering Mathematics, Khanna Publishars, 40th

Edition, 2010.

3. E. Kreyszig, โ€œAdvanced Engineering Mathematicsโ€, John Wiley and Sons, New York, 2005.

4. B.V. Ramanna, โ€œHigher Engineering Mathematicsโ€, Tata Mcgraw Hill Publishing Company Ltd.,

2008.

5. R.K. Jain and S.R.K. Iyengar, โ€œAdvanced Engineering Mathematicsโ€, Narosa Publishing House,

2008.

Government Engineering College, Nawada

Department of Applied Science & Humanities (Mathematics)

Tutorial Sheet-III Session : 2019-20(Even Sem.) Semester : II

Course/

Branch

: B. Tech./ ME Paper Name : Mathematics-II

(102202)

Module : 4 Topic Covered : Complex Variables-

Differentiation

Name of Faculty: Dr. Rajnesh Kumar

Note: Following are the problems which are required to be done by the students for an overall

understanding of the topics.

1. Check whether the following limits exist or not

(i)z

zz

z

)Im()Re(lim

0โ†’, (ii)

0limz

z

zโ†’, (iii)

2

20

Imlimz

z

zโ†’.

2. Find out whether the following functions are continuous at origin or not, where (0) 0f = ,

(i) 2

2

Re z

z, (ii)

2Im z

z, (iii)

2 1Rez

z

.

3. Examine the differentiability of the following complex valued functions

(i) ( )f z z= at origin, (ii) 2

( )f z z= at 0z = , (iii) 2( )f z z= .

4. Determine the analyticity of the following functions.

(i) zzf sin)( = , (ii) )(2)( 22 yxixyzf ++= , (iii) 2( ) (cosh sinh )xf z e y i y= + .

5. Show that the function ,)(4โˆ’โˆ’= zezf z 0 and 0)0( =f is not analytic at the origin even through

CR equation are satisfied.

6. Examine which of the following functions are harmonic:

(i) 23 34),( xyxyxyxu โˆ’โˆ’= , (ii) )sincos(),( yyyxeyxu x += โˆ’ .

7. Using the C-R equations find the harmonic conjugate of the following functions

(i) yxxyyxu 32222 +โˆ’โˆ’โˆ’= , (ii) )log(2

1),( 22 yxyxu +=

where, ( )f z u iv= + is an analytic function.

8. Find the analytic function f(z) using Milne โ€“Thomson method:

(i) yxu coshcos= (ii) ).4)((),( 22 yxyxyxyxu ++โˆ’=

9. Show that the function ivuzf +=)( , where

=

+

+

=

0,0

0,)(

)( 104

52

z

zyx

iyxyx

zf

Satisfies the Cauchy-Riemann equations at 0=z . Is the function analytic at 0=z ?

10. Deterrmine the analytic function ( )f z u iv= + , if )cosh(cos2

sincos

yx

exxvu

y

โˆ’

โˆ’+=โˆ’

โˆ’

and .0)2( =

f

11. Prove that an analytic function with constant modulus is constant.

12. Find the bilinear transformation which maps the points 2zi,z2,z 321 โˆ’=== into the points

1wi,w1,w 321 โˆ’=== .

13. Discuss the application of the transformation iz

1izw

+

+= to the areas in the z-plane which are

respectively inside and outside the unit circle with its centre at the origin. 14. Find the general homographic transformation which leaves the unit circle invariant. 15. Every bilinear transformation maps circles or straight lines into circles or straight lines.

16. Show that the transformation ,tanh 1 zw โˆ’= maps the upper half of the z -plane conformally on the

strip .2

10 v

17. Show that the resultant (or product) of two bilinear transformations is a bilinear transformation. Explain the concept of isogonal mapping and conformal mapping with illustrative examples.

18. Find the fixed points and the normal of the following bilinear transformation: (i)2โˆ’

=z

zw (ii)

.1

1

+

โˆ’=

z

zw

19. Show that the line x3y = is map onto the circle under the bilinear transformation iz

izw

+

+=

4

2. Find

the centre and radius of image circle. 20. Find the bilinear transformation that maps the point 0zi,z,z 321 === into the points

=== 321 wi,w0,w .

21. Show that the inverse of the point a with respect to the circle R=c-z is the point )(

Rc

2

ca โˆ’+ .

Text / Reference Books: 1. R. K. Jain & S. R. K. Iyengar. โ€œAdvanced Engineering Mathematics,โ€ Narosa Publishing House Pvt.

Ltd., 3 Ed., 2011

2. J. K. Goyal & K. P. Gupta. โ€œFunctions of a Complex Variable,โ€ Pragati Prakashan., 17th edition 2003

3. Shanti Narayan & P.K. Mittal. โ€œ Theory of Functions of a Complex Variable,โ€ S. Chand Revised Ed,

2010

4. Ruel V. Churchill, Complex variables and Applications

5. S. Ponnusamy. โ€œFoundation of Complex Analysis,โ€ Narosa Publishing House Pvt. Ltd., 2nd Ed. 2005

6. M. R. Spiegel. โ€œTheory of Complex Variable,โ€ Mc - Graw HiIl Publication, 1981.

7. Murray Spiegel, Seymour Lipschutz, John Schiller & Dennis Spellman. โ€œ Schaum's Outline of

Complex Variables, 2edโ€

Government Engineering College, Nawada

Department of Applied Science & Humanities (Mathematics)

Tutorial Sheet-IV Session : 2019-20(Even Sem.) Semester : II

Course/

Branch

: B. Tech./ ME Paper Name : Mathematics-II

(102202)

Module : 5 Topic Covered : Complex Variables-

Integration

Name of Faculty: Dr. Rajnesh Kumar

Note: Following are the problems which are required to be done by the students for an overall

understanding of the topics.

1. If a function )(zf is analytic for finite values of z , and is bounded, then )(zf is constant.

2. Find upper bound of integral โˆ’

+

C

iz

dzz

zLogez

2

)3(2

3

, 3/0,2: == iezzC .

3. What curve is represented by the function 36)2(9)1(4 22 =++โˆ’ yx .

4. Find the value of the integral dzixyx

i

+

+โˆ’

21

0

32 )3( along the real axis from 0=z to 1=z and then, along

a line parallel to the imaginary axis from 1=z to iz 21+= .

5. Use ML-inequality to show that 2

1

12

+C

dzz

zwhere C is the straight line segment from 2=z to

iz += 2 .

6. Find the value of the integral izdzzz

e

C

z

4,)2)(1(

2

=โˆ’โˆ’ .

7. Find the value of the integral dyxy

ydx

yx

x

C

2222 โˆ’+

โˆ’ where C is the boundary of the triangle with the

vertices (2, 0), (4, 0) and (4, 3).

8. State and prove fundamental theorem of integral calculus.

9. Evaluate the following integrals by Cauchyโ€™s integral formula

a. dzz

zzc โˆ’

++

2

652

where c is the circle 13 == zandz ,

b. โˆ’

cdz

z

z

2

2

)6

(

sin

where c is the circle 1=z ,

c. โˆ’c

dzz 1

1

2 where c is the circle 2=z .

10. If the curve 20),exp()( = titt then find the integral +

+

dzz

z

)1(

12

.

11. If Cwzwfzfwzf +=+ ,)()()( and )(zf is analytic in C , show that czzf =)( , where c is

constant.

12. Prove that non constant entire function is unbounded.

13. Suppose )(zf is entire function such that 2

)( zzf , ifif == )2(,2)1( find )(zf .

14. Find the radius of convergence of the following power series (i)

++

n

1iz

i 2(ii)

n

nz

2

n i2

+.

15. Find the radius of convergence of the following power series:

a.

= +=

0 14)(

nn

nzzf

b. .!

)(

0

=

=

nn

n

n

znzf

16. Find the region of convergence of the series (i)

=1n

n

n log

z (ii) ( )

( )

=

โˆ’โˆ’

โˆ’โˆ’

1

121

!121

n

nn

n

z.

17. Find the first four terms of the Taylorโ€™s series expansion of the function

)(tan)( 1 zzf โˆ’= about 0=z .

18. Obtain the Taylor and Laurentโ€™s series which represents the function 3)2)(z(z

1z2

++

โˆ’ in the regions (i)

2z (ii) 32 z (iii) 3z .

19. Expand )2)(1(

23)(

++

โˆ’=

zzz

zzf in Laurentโ€™s series valid for region .3|2|1 + z

20. Expand )9(

1897)(

3

2

zz

zzzf

โˆ’

โˆ’+= in the region (i) 3||0 z (ii) 3z (iii) 21 z .

21. Find the kind of singularity of the function

โˆ’=

z-1

1sin

2zf(z)

2z.

22. What kind of singularity has the function

(i)

=

z

1cos

1f(z)

at 0=z (ii) ( )1/z cosec

at =z .

23. Discuss the singularity of the following functions:

a. z

ezf

z/1

)( =

b. .11

1cos)( =

โˆ’= zat

zzf

24. Find the poles and residue of the poles of the following function:

)3)(4)(2(

)(4

++โˆ’=

zzz

zzf

25. Determine the nature of the pole at the origin of the function mzz sin

ef(z)

z

= .

26. Show that the function 21/zeโˆ’ has no singularities.

27. Find the residue of zcot(z) = at the points n=nz for 1,2,...n = what is the nature of singularity at

=z ? Justify your answer.

28. If an analytic function f(z) has a pole of order m at a=z , then 1/f(z)has a zero of order m at a=z

and conversely.

29. If a=z is an isolated singularity of f(z) and if f(z) is bounded on some deleted neighborhood of a ,

then prove that a is a removable singularity.

30. Find residues of (i)2zz

12z2 โˆ’โˆ’

+ (ii)

12

3

โˆ’z

z at .=z

31. Evaluate (i) +

2ฯ€

0

2

cosba

dsin

(ii) dx

+0

22

2

)1(x

x.

32. By contour integration, prove that 4x

xsin

0

2 =

dx

.

33. Evaluate the following integrals using Cauchy Residue Theorem:

a.

2:;)12()1(

75

2=

+โˆ’

โˆ’ zCdz

zz

z

c

b. .2:;)4)(1(

12

2

2

=+โˆ’

+

C

zCdzzz

z

34. Evaluate the following integrals by contour integration:

a. +

2

0 cos45

d

b. .cos45

2cos2

0

โˆ’

d

35. Apply calculus of residue to prove that:

โˆ’=

+โˆ’

2

0

2

2

2,

1

2

cos21

2cos

a

a

aa

d (a2 < 1 ).

36. Evaluate the following integrals by contour integration:

a.

โˆ’ + )1( 2x

dx

b.

+022

.)(

sindx

ax

xx

37. Evaluate the following integrals using Cauchy Residue Theorem:

=โˆ’โˆ’

+โˆ’

C

zCdzzz

zz1:;

)13()12(

523302

2

.

38. Apply calculus of residue to prove that:

.0);1(2)(

sin

222โˆ’=

+

โˆ’ ae

adx

axx

mx ma

C

39. Verify the integral ,sin1x

x

0

-a

adx =

+

10 a .

40. Let f(z) be analytic in Rz

and Mf(z)

onRz =

. Then prove that .R

M(0)'f

Text / Reference Books: 1. R. K. Jain & S. R. K. Iyengar. โ€œAdvanced Engineering Mathematics,โ€ Narosa Publishing House Pvt.

Ltd., 3 Ed., 2011

2. J. K. Goyal & K. P. Gupta. โ€œFunctions of a Complex Variable,โ€ Pragati Prakashan., 17th edition 2003

3. Shanti Narayan & P.K. Mittal. โ€œ Theory of Functions of a Complex Variable,โ€ S. Chand Revised Ed,

2010

4. Ruel V. Churchill, Complex variables and Applications

5. S. Ponnusamy. โ€œFoundation of Complex Analysis,โ€ Narosa Publishing House Pvt. Ltd., 2nd Ed. 2005

6. M. R. Spiegel. โ€œTheory of Complex Variable,โ€ Mc - Graw HiIl Publication, 1981.

7. Murray Spiegel, Seymour Lipschutz, John Schiller & Dennis Spellman. โ€œ Schaum's Outline of

Complex Variables, 2edโ€