Write complex expressions in standard form a + bi — simplify powers of i, square roots of negative numbers, and combined expressions.
i¹ = i | i² = −1 | i³ = −i | i⁴ = 1
The powers of i repeat with period 4. To find in for any integer n, compute n mod 4:
n mod 4 = 0 → i⁴ = 1 | n mod 4 = 1 → i¹ = i
n mod 4 = 2 → i² = −1 | n mod 4 = 3 → i³ = −i
Example: i¹⁵ → 15 mod 4 = 3 → i³ = −i
√(−a) = i√a for a > 0
A complex number in standard form is a + bi where:
a = real part | b = imaginary part | i = √(−1)
To simplify √(−n): factor out √(−1) = i, then simplify √n by pulling out perfect square factors.
Example: √(−12) = i√12 = i√(4·3) = 2i√3
One-on-one Algebra 2 tutoring makes the imaginary unit click — we work through your actual problems and build the intuition that sticks for tests and beyond.