FAST-NU Advanced Mathematics — Complex Numbers
Complex Numbers is part of the Advanced Mathematics section of FAST's BS CS/Engineering admission test (usually 50 of the 120 MCQs, 50% of the marks). It breaks into 4 subtopics, and we hold 41 FAST-pattern practice MCQs on it, each with a written explanation. Tap a subtopic below to practise just that.
Subtopics (4)
How Complex Numbers is tested
Across the 7 FAST-pattern papers on ParhaiKrlo, Complex Numbers accounts for 14 questions. It appears in all 7, about 2 questions a paper. The heaviest was FAST Past Paper 07, with 2 questions.
| Paper | Questions |
|---|---|
| FAST Past Paper 07 | 2 |
| FAST Past Paper 06 | 2 |
| FAST Past Paper 05 | 2 |
| FAST Past Paper 04 | 2 |
| FAST Past Paper 03 | 2 |
| FAST Past Paper 02 | 2 |
| FAST Past Paper 01 | 2 |
Complex Numbers MCQs from the FAST-pattern papers
Try each one before opening the answer. Each comes with a short explanation.
- Q1 · FAST Past Paper 07 · Complex Numbers
(2 + 3i) + (4 − i) is equal to:
- A.8 + 3i
- B.6 + 2i
- C.6 + 4i
- D.2 − 4i
Show answer
Answer: B. 6 + 2i — Add real parts and imaginary parts: (2 + 4) + (3 − 1)i = 6 + 2i.
- Q2 · FAST Past Paper 06 · Complex Numbers
The value of i¹⁰¹ + i¹⁰² is:
- A.1 + i
- B.−1 + i
- C.−1 − i
- D.0
Show answer
Answer: B. −1 + i — 101 leaves remainder 1 and 102 remainder 2 on division by 4, so the sum is i + (−1) = −1 + i.
- Q3 · FAST Past Paper 05 · Complex Numbers
If (x + iy)(2 − i) = 5, where x and y are real, then (x, y) is:
- A.(2, −1)
- B.(2, 1)
- C.(1, 2)
- D.(5/2, 0)
Show answer
Answer: B. (2, 1) — x + iy = 5/(2 − i) = 5(2 + i)/(4 + 1) = 2 + i, so (x, y) = (2, 1).