Khan Academy

Sine & cosine of complementary angles-video (K-A)

Trig word problem: complementary angles (K-A)

Using complementary angles (K-A)

Trig ratios of special triangles (K-A)

Intro to the Pythagorean trig identity (K-A)

Finding reciprocal trig ratios (K-A)

Reciprocal trig ratios (K-A)

Trigonometric ratios review (K-A)

Using reciprocal trig ratios (K-A)

i as the principal root of -1 (K-A)

Intro to the imaginary numbers (K-A)

Intro to the imaginary numbers-video (K-A)

Powers of the imaginary unit (K-A)

Powers of the imaginary unit-link (K-A)

Simplifying roots of negative numbers (K-A)

Classifying complex numbers (K-A)

Intro to complex numbers (K-A)

Intro to complex numbers-video (K-A)

Plotting numbers on the complex plane (K-A)

The complex plane-link (K-A)

Adding complex numbers (K-A)

Subtracting complex numbers (K-A)

Complex number operations review (K-A)

Multiplying complex numbers-link (K-A)

Multiplying complex numbers-video (K-A)