← Back to Test

Problem 14 - Entrance Test

Let i be the imaginary unit, i^2 = -1. Find the value of (1 + i)^10.

Correct: C

We need to calculate (1 + i)^10. It's often easier to first calculate a smaller power and then raise it to the remaining power. Let's calculate (1 + i)^2: (1 + i)^2 = 1^2 + 2(1)(i) + i^2 Since i^2 = -1: (1 + i)^2 = 1 + 2i - 1 = 2i. Now we can rewrite (1 + i)^10 as ((1 + i)^2)^5: (1 + i)^10 = (2i)^5. Next, we apply the exponent to both the coefficient and the imaginary unit: (2i)^5 = 2^5 * i^5. Calculate 2^5: 2^5 = 32. Calculate i^5. The powers of i follow a cycle of 4: i^1 = i i^2 = -1 i^3 = -i i^4 = 1 i^5 = i^4 * i = 1 * i = i. Substitute these values back: (1 + i)^10 = 32 * i = 32i.