Arithmetic and conjugates
Meet , where . Add, subtract and multiply complex numbers like brackets, divide using the conjugate, and solve equations by equating real and imaginary parts.
≈ 35 minThe Argand diagram, modulus and argument
Plot as the point . Its distance from the origin is the modulus , and its angle from the positive real axis is the argument , with .
≈ 35 minPolynomial equations and square roots
Every quadratic now has two roots. For polynomials with real coefficients, complex roots come in conjugate pairs, which lets you find all the roots from one. Square roots of come from equating real and imaginary parts.
≈ 40 min