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Determine the square roots of the following complex numbers: (a) 9 + 40i (b) -11 - 60i (c) 50i

1. (a) +-(5 + 4i), (b) +-(5 - 6i), (c) +-(5 + 5i)
2. (a) +-(4 + 5i), (b) +-(6 - 5i), (c) +-(5 - 5i)
3. (a) +-(5 + 4i), (b) +-(6 - 5i), (c) +-(5 + 5i)
4. (a) +-(5 - 4i), (b) +-(5 + 6i), (c) +-(5 + 5i)

Correct answer: (a) +-(5 + 4i), (b) +-(5 - 6i), (c) +-(5 + 5i)

Solution

Writing the root as x+yi and squaring gives two equations; solving yields the integer-valued roots.

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