Gujarat Technological UniversitySummer 2025 examination

GTU 2141905 Complex Variables and Numerical Methods Summer 2025 Question Paper & PDF

B.E. · Mechanical Engineering · Semester 4 · Subject code 2141905
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Total
70 marks
To pass
23 marks (33%)
Duration
2.5 Hours 10:30 AM – 1:30 PM
Questions
5 with internal choice
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12 of 25 questions are types of question GTU sets again with new data. Each is marked below with the years it appeared.See all 12 repeated 2141905 questions, most asked first

Q.1

14 Marks
(a)
3 marksSame type asked in 2 of 2 papers

Discuss continuity of 𝑓(𝑧) = { 𝑅𝑒(𝑧²) |𝑧|2 ; 𝑧 ≠ 0 0 ; 𝑧 = 0 at z = 0.

Also asked in Summer 2026 Q1b

(b)
4 marks
Find the analytic function 𝑓(𝑧) = 𝑢 + 𝑖𝑣, if 𝑢 − 𝑣 = 𝑒𝑥(𝑐𝑜𝑠𝑦 − 𝑠𝑖𝑛𝑦).
(c)
7 marksSame type asked in 2 of 2 papers

Find the Laurent’s series expansion of 𝑓(𝑧) = 1 𝑧(𝑧²−3𝑧+2) about z = 0, for the regions

i)1 < |𝑧| <2 Marks
ii)|𝑧| > 2.

Also asked in Summer 2026 Q3c

Q.2

14 Marks
(a)
3 marks

Evaluate the integral ∫ 𝑑𝑥 1+𝑥2 1 −1 by Gaussian integration two pint formula.

(b)
4 marksSame type asked in 2 of 2 papers

Evaluate ∫ (𝑠𝑖𝑛𝑥 − 𝑙𝑜𝑔𝑥 + 𝑒𝑥)𝑑𝑥 1.4 0.2 with h=0.2 by simpson’s 1/3rd and 3/8th rule.

Also asked in Summer 2026 Q5a OR

(c)
7 marksSame type asked in 2 of 2 papers

Use the power method to find the largest eigen value and corresponding eigen vector of the matrix 𝐴 = [ 1 6 1 1 2 0 0 0 3 ]

Also asked in Summer 2026 Q4c OR

(c)
7 marksSame type asked in 2 of 2 papers
Solve the following system of equations using Gauss seidel method:

5𝑥 + 𝑦 − 𝑧 = 10 ; 2𝑥 + 4𝑦 + 𝑧 = 14 ; 𝑥 + 𝑦 + 8𝑧 = 20

Also asked in Summer 2026 Q5c OR

Q.3

14 Marks
(a)
3 marks

Use secant method to estimate the root of 𝑐𝑜𝑠𝑥 = 𝑥𝑒𝑥 correct to four significant digits

(b)
4 marksSame type asked in 2 of 2 papers

Find a real root of 𝑥𝑒𝑥 = 2, correct up three decimal places, by using Newton- raphson method

Also asked in Summer 2026 Q4b

(c)
7 marks

Compute f (9.2) from the following value Newton’s divided difference formula. X 8.0 9.0 9.5 11 F(x) 2.079442 2.197225 2.251292 2.397895

(a)
3 marksSame type asked in 2 of 2 papers

Use trapezoidal rule to evaluate ∫ 𝑥³𝑑𝑥 1 0 considering five sub intervals.

Also asked in Summer 2026 Q4a OR

(b)
4 marks

Using Newton’s forward formula, find the value of f(1.6) if X 1 1.4 1.8 2.2 F(x) 3.49 4.82 5.96 6.5

(c)
7 marksSame type asked in 2 of 2 papers

Solve the following system of equation by gauss elimination method with partial pivoting 2𝑥1 + 2𝑥2 + 𝑥3 = 6; 4𝑥1 + 2𝑥2 + 3𝑥3 = 4 ; 𝑥1 + 𝑥2 + 𝑥3 = 0

Also asked in Summer 2026 Q1c, Summer 2026 Q4c

Q.4

14 Marks
(a)
3 marks

If 𝑓(𝑧) = 𝑢 + 𝑖𝑣 is analytic in domain D then prove that ( 𝜕2 𝜕𝑥2 + 𝜕2 𝜕𝑦2) |𝑅𝑒𝑓(𝑧)|2 = 2|𝑓′(𝑧)|2.

(b)
4 marks

Determine the poles of the function 𝑓(𝑧) = 𝑧2 (𝑧−1)²(𝑧+2) and residue at each pole. Evaluate ∫ 𝑓(𝑧)𝑑𝑧, 𝑐 where c is the circle |𝑧| = 3.

(c)
7 marks

Show that the function 𝑓(𝑧) = √|𝑥𝑦| satisfies the Cauchy- Riemann equations at the origin but 𝑓′(0) fails to exits.

(a)
3 marks

Expand 𝑓(𝑧) = 𝑧−1 𝑧+1 as a Taylor’s series about the point z = 1.

(b)
4 marksSame type asked in 2 of 2 papers

Find the radius of converges of ∑ (6𝑛+1 2𝑛+5)2 (𝑧 − 2𝑖)𝑛. ∞ 𝑛=1

Also asked in Summer 2026 Q3b OR

(c)
7 marks

Simplify (1+𝑠𝑖𝑛𝜋 8+𝑖𝑐𝑜𝑠𝜋 8 1+𝑠𝑖𝑛𝜋 8−𝑖𝑐𝑜𝑠𝜋 8 )

Q.5

14 Marks
(a)
3 marksSame type asked in 2 of 2 papers
Find the fourth root of -1

Also asked in Summer 2026 Q2b

(b)
4 marks
Prove that sinh⁻¹ 𝑥 = 𝑙𝑜𝑔{𝑥 + √𝑥² + 1}.
(c)
7 marks

Prove that the nth root of unity are in geometric progression with the common ratio (cos 2𝜋 𝑛 + 𝑖 sin 2𝜋 𝑛 )and show that the continued product of all 𝑛𝑡ℎ roots is (−1)𝑛+1.

(a)
3 marksSame type asked in 2 of 2 papers
Find the image of infinite strip 0 ≤ 𝑥 ≤ 1 under the transformation 𝑤 = 𝑖𝑧 + 1.

Sketch the region in the w-plane.

Also asked in Summer 2026 Q3a

(b)
4 marksSame type asked in 2 of 2 papers

Show that 𝑢 = 𝑥² − 𝑦² + 𝑥 is harmonic, Find the corresponding analytic function 𝑓(𝑧) = 𝑢 + 𝑖𝑣

Also asked in Summer 2026 Q2c

(c)
7 marks

Using Cauchy’s Integral formula, evaluate ∮ 1 𝑧²−7𝑧+12 𝑑𝑧, where C is the circle |𝑧| = 3.5

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About this paper

Official Gujarat Technological University (GTU) examination paper for Complex Variables and Numerical Methods (Summer 2025, B.E. · Mechanical Engineering, Sem 4). Features complete 70-mark regular & remedial examination pattern, official marking distribution across all 5 questions, and direct 1-click official PDF download.

Transcribed for student exam preparation from Gujarat Technological University official examination archives. Questions, syllabus guidelines, and curriculum marking schemes remain the intellectual property of Gujarat Technological University.

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