What is (1 + i)^2, where i is the imaginary unit with i^2 = -1?
Answer and explanation
Correct answer: B. 2i, because 1 + 2i + i^2 = 2i
- Step 1: Expand: (1 + i)^2 = 1 + 2i + i^2. Step 2. Since i^2 = -1, this is 2i. Answer: 2i. Why not the others: (a + b)^2 is not a^2 + b^2, and the real parts do cancel but the middle term stays.
Practise more Mathematics.
Free questions with an explanation for every one, and full timed FUVEST (University of São Paulo Entrance Exam) mock tests.
More Mathematics questions
- Solve the equation 3x - 7 = 11.
- What is the slope of the straight line through the points (1, 2) and (3, 8)?
- What are the roots of x^2 - 5x + 6 = 0?
- An arithmetic sequence has first term 3 and common difference 4. What is the sum of its first 10 terms?
- What is the value of log base 2 of 32 plus log base 3 of 9?
- Let f(x) = 2x + 1 and g(x) = x^2. What is f(g(3))?