All articles
9 min read

Complex Analysis Course for CSIR NET and GATE: What to Check

A complex analysis course suits CSIR NET and GATE only if it covers every block your exam syllabus names and includes timed tests with solutions. Check the topic list before the price.

By Sunil Bansal, Founder · Updated 14 Oct 2026

A student at a desk by a window sketches a looping contour on the complex plane in a notebook.

Key takeaways

  • Buy a complex analysis course only if its lecture list names every block your exam tests (the table shows which exam names which of the eight blocks) and it includes timed tests with worked solutions.
  • Free lectures are enough for the theory if you can set your own pace. NPTEL (the National Programme on Technology Enhanced Learning) has a 40-lecture course from the Indian Institute of Technology (IIT) Guwahati. Pay when you need exam practice, solutions and someone to ask.
  • Choose a contour from where the singularities sit and how fast the integrand decays: a large semicircle, a semicircle with a small indent around a pole on the real axis, or a keyhole around a branch cut.
  • Our Complex Analysis Master Course is taught by SB Sir in Hinglish (a mix of Hindi and English) and costs ₹2,499 as of October 2026. Free demo classes, notes and previous-year questions let you try our teaching first.

In this article
  1. 1What should a complex analysis course cover for CSIR NET and GATE?
  2. 2Is a free complex analysis course enough, or should you pay for one?
  3. 3How do you choose the right contour for a real integral?
  4. 4How can you test a complex analysis course before paying?
  5. 5Does the lecture list name every block your exam needs?
  6. 6Can you watch a full lecture first?
  7. 7Are there timed tests with worked solutions?
  8. 8Does access outlast your exam?
  9. 9What does our complex analysis course include?
  10. 10Frequently asked questions

Two complex analysis courses can teach the same theorems and leave you in very different places on exam day. Complex analysis is the calculus of functions of a complex number, z = x + iy. In the Graduate Aptitude Test in Engineering (GATE) 2026 Mathematics (MA) paper, 2,559 of the 11,561 candidates who appeared qualified (GATE 2026 Statistical and Performance Report, table 2), and the paper has a named complex analysis section.

The Council of Scientific and Industrial Research National Eligibility Test (CSIR NET) and GATE ask for more than a first course delivers. You must pick the right contour, spot the type of singularity and apply a theorem in a minute or two, with no lecturer to guide you.

Popularity and lecture count say little about that. What matters is whether the course drills the lines your exam tests. Below are those lines, a checklist you can run on any course, a worked contour example and a plain view on when free lectures are enough.

What should a complex analysis course cover for CSIR NET and GATE?

A complex analysis course for CSIR NET and GATE should cover eight blocks: the plane and power series, analytic and harmonic functions, contour integration, Liouville's theorem and its relatives, Taylor and Laurent series, singularities and residues, Rouché's theorem with the argument principle, and Möbius maps. The official syllabi name each one.

Not every exam names every block. The table shows which syllabus names what. The last column is a test you can run on any lecture list. CUET PG is the Common University Entrance Test for Postgraduate admission, and SCQP19 is its Mathematics paper code.

BlockWhat the syllabi namePass test for a lecture list
1. Plane, power series, elementary functionsCSIR NET: complex numbers, the complex plane, power series, exponential, trigonometric and hyperbolic functions. GATE MA: power series, radius of convergence. CUET PG: power series as an analytic function.Pass: a lecture that finds a radius of convergence, and one treating exp, sin, cos and sinh as complex functions.
2. Analytic and harmonic functionsCSIR NET: analytic functions, Cauchy-Riemann equations. GATE MA: differentiability, analytic and harmonic functions. CUET PG: the same, with harmonic functions.Pass: given u(x, y), the lectures find the harmonic conjugate v and then f(z).
3. Contour integration and Cauchy's resultsCSIR NET: contour integral, Cauchy's theorem and integral formula. GATE MA: Cauchy's integral theorem and formula. CUET PG: line integrals, Goursat's theorem, index of a closed curve, Cauchy's integral formula.Pass: one circle integral done by the definition and again by the integral formula.
4. Liouville and related theoremsCSIR NET: Liouville, maximum modulus, Schwarz lemma, open mapping theorem. GATE MA: Liouville, maximum modulus, Morera, Schwarz lemma. CUET PG: Morera, Liouville, fundamental theorem of algebra.Pass: each theorem your exam names is stated and then used on a question, such as bounded entire functions.
5. Taylor and Laurent series, zerosCSIR NET: Taylor and Laurent series. GATE MA: Taylor and Laurent series, zeros.Pass: one function expanded in two different annuli (rings between two circles).
6. Singularities and residuesCSIR NET: calculus of residues. GATE MA: zeros and singularities, residue theorem and its use for real integrals.Pass: classify removable, pole and essential singularities, find residues, and close a contour to evaluate a real integral.
7. Rouché and the argument principleGATE MA: Rouché's theorem, argument principle.Pass: count the zeros of a polynomial inside |z| < 1 using Rouché's theorem.
8. Conformal maps and Möbius transformationsCSIR NET and GATE MA: conformal mappings, Möbius transformations.Pass: build the Möbius map taking three given points to three given points.

Sources: the CSIR NET Mathematical Sciences syllabus, Unit 2, the Complex Analysis section of the GATE 2027 MA syllabus and the CUET PG Mathematics (SCQP19) syllabus.

The CUET PG complex analysis unit ends at Cauchy's integral formula, Morera's theorem, Liouville's theorem, the fundamental theorem of algebra and harmonic functions. For that paper, blocks 1 to 4 are the ones to check. For the rest of the CSIR NET paper, see our guide to the CSIR NET Mathematical Sciences syllabus.

Is a free complex analysis course enough, or should you pay for one?

Free lectures are enough for the theory if you can set your own pace and find your own practice. Pay when you want timed tests with solutions, a fixed schedule and someone to ask. We publish this page, and our own course is one of those compared.

OptionWhat it givesBuilt for
40 lectures: 1 introduction, 5 on the plane and its topology, 8 on limits and differentiation, 10 on integration, 7 on further properties of analytic functions, 3 on Möbius maps, 6 on singularities and residuesA university first course. Prerequisite: single and multivariable real analysis.
Our free study contentDemo classes, notes, previous-year questions and a PDF Drive, all without paymentA first look at how we teach, and practice material for any course
Taught by SB Sir in Hinglish, with quizzes and live testsCSIR NET and GATE preparation

Our recommendation:

  • Comfortable with real analysis and good at working alone: use NPTEL for the theory and add past papers.
  • Months, not a year, before the exam: take a course with tests and solutions, because lectures alone do not show which questions cost you marks.
  • Sitting CUET PG only: you need blocks 1 to 4 and no more.

If you also want a textbook, NPTEL's reference list names Priestley's Introduction to Complex Analysis (Indian edition), Ahlfors, and Brown and Churchill. Our guide to CSIR NET maths books explains how to settle on one main book.

Start with our free study content and the PDF Drive. For CSIR NET and GATE together, our 2027 course costs ₹15,999 (or four instalments of ₹3,999.75) with access through 30 June 2027, as of October 2026, and includes doubt support. A ₹999 Demo Plan with 10 days of access lets you try it first.

How do you choose the right contour for a real integral?

Choose the contour from where the singularities sit and how the integrand behaves on the arc. Close a large semicircle when the integrand shrinks fast enough, indent around a pole on the real axis, and use a keyhole only when the integrand has a branch cut. Learners ask exactly this: "What are the guidelines for choosing a contour? Does it matter?" and "Would it be some kind of keyhole contour?"

A hand draws a large semicircular contour above a straight line with small points marked inside it.
The arc, the marked points and the small indent show how the singularities decide the path.
IntegrandContour
Rational function with denominator degree at least 2 more than the numerator, no real polesLarge upper semicircle
e^(iaz) times a function that tends to 0, with a > 0Upper semicircle, using Jordan's lemma (the arc integral vanishes as the radius grows)
Simple pole on the real axisSame semicircle plus a small indent around the pole
Fractional power or logarithm, range 0 to ∞Keyhole around the branch cut

The semicircle is there because the residue theorem works only on closed curves, and the real line is not closed. The arc closes it and is chosen so that its integral tends to zero.

Worked example. To evaluate the integral of 1/(x² + 1) over the whole real line, close the contour with the upper semicircle of radius R > 1. On the arc, |z² + 1| ≥ R² − 1, so the arc integral is at most πR/(R² − 1), which tends to 0. The only pole inside is z = i, with residue 1/(2i). The integral is 2πi × 1/(2i) = π.

For sin x / x, use e^(iz)/z, indent above the pole at 0, and the small arc contributes −iπ. The integral of e^(ix)/x then equals iπ in the principal-value sense, and its imaginary part gives π.

The GATE MA syllabus names "residue theorem and applications for evaluating real integrals". A course that skips a worked set of these fails block 6 in the table.

How can you test a complex analysis course before paying?

Run four checks on any course page, each with a clear pass or fail. They take about ten minutes and cost nothing.

Does the lecture list name every block your exam needs?

Pass: every block your exam names in the table above has a lecture or session named for it. Fail: a block you need appears only inside a general "revision" or "practice" lecture, where you cannot tell what is taught.

Can you watch a full lecture first?

Pass: a complete sample lecture or demo class, long enough to judge the pace and the language. Fail: only a trailer. Digital courses are rarely refundable, so the sample is your only trial.

Are there timed tests with worked solutions?

Pass: tests that cover each block your exam names, in the question formats of your exam, each followed by a solution walkthrough. Fail: practice sheets with answers only. For how the papers are built, see our guide to the CSIR NET exam pattern for maths.

Does access outlast your exam?

Pass: access ends at least a month after your exam date, which leaves a revision month. This is our recommendation. Fail: access that ends before the exam.

A student pauses a lecture video on a laptop with a notebook and a small timer on the desk.
Pausing a sample lecture and timing yourself is the cheapest way to judge a course before you pay.

What does our complex analysis course include?

Our Complex Analysis Master Course is taught by SB Sir (Sunil Bansal) in Hinglish and costs ₹2,499 as of October 2026. It is built for CSIR NET and GATE. SB Sir secured All India Rank 11 in CSIR NET in December 2017 and is GATE MA qualified. He teaches pure mathematics at SBTech Math.

The course covers analytic functions, Cauchy-Riemann equations, complex integration, Liouville's theorem, power series, singularities, residues, the Schwarz lemma, the argument principle and bilinear transformations, another name for Möbius maps. The platform provides quizzes and live tests to practise on. Those topics sit in blocks 1 to 4, 6, 7 (the argument principle) and 8.

Run the checks above on our course too. Try a demo class first, and ask us where Taylor and Laurent series and Rouché's theorem are taught and whether the tests come with worked solutions. You should expect clear answers before you pay.

To buy, add the course to your cart, check out, and find it under My Courses. Registration needs your name and email address. We do not refund digital products, though we will consider a serious health issue straight after purchase, so use the demo classes first. Support runs from 9am to 7pm, Monday to Saturday.

If you are unsure whether you need one subject or a full CSIR NET and GATE course, tell us your exam and attempt on our contact page, and we will point you to the right one.

Try a Complex Analysis demo class first

Tell us your exam and attempt, and we will point you to the right SBTech Math course.
Contact SBTech Math

Frequently asked questions

Give it a fixed block. At five lectures a week, NPTEL's 40 lectures take eight weeks (40 ÷ 5). Our recommendation is to spend about as long again on timed questions, so a first pass plus practice runs to roughly four months.
Follow the order the theory builds. NPTEL's course goes from the complex plane and its topology to limits and differentiation, then integration, then power series and zeros, then Möbius maps, and finally singularities, residues and the argument principle.
Yes. Our Complex Analysis course is taught in Hinglish, a mix of Hindi and English, and we support learners in Hindi and English. A demo class lets you judge whether the mix suits you.
We offer free notes, previous-year questions, demo classes and a PDF Drive on our site, open without payment. Use them to test your level before choosing any course.
It covers most of the theory in the CSIR NET unit. Exam marks, though, depend on applying a theorem in a minute or two, so pair it with timed past-paper questions.

Sources

  1. 1.GATE 2026 Statistical and Performance Report, IIT Guwahati
  2. 2.NPTEL Complex Analysis video course outline, IIT Guwahati
  3. 3.CSIR-UGC NET Mathematical Sciences syllabus, Unit 2
  4. 4.GATE 2027 Mathematics (MA) syllabus, IIT Madras
  5. 5.CUET PG Mathematics (SCQP19) syllabus
  6. 6.Physics Forums: How to use contour, complex analysis to solve integrals?
  7. 7.Physics Forums: Complex contour integral, which one do I use?

Keep reading

SBTechMath.

India's trusted Mathematics learning platform for CSIR-NET, GATE, IIT-JAM, CUET PG, and competitive exam aspirants. Learn concepts that help you succeed.

© 2026 SBTech Math

Powered by PageLens.ai

Crack CSIR-NET, GATE & IIT-JAM with concept-first learning.

Start Now