虚数不虚

工程中，大量运用到复变函数。一直以来对复数感到陌生，看了以下教学视频颇有启发。视频分成10个部分：

• Part 1: Introduction
• Part 2: A Little History
• Part 3: Cardan’s Problem
• Part 4: Bombelli’s Solution
• Part 5: Numbers are Two Dimensional
• Part 6: The Complex Plane
• Part 7: Complex Multiplication
• Part 8: Math Wizardry
• Part 9: Closure
• Part 10: Complex Functions
• Part 11: Wandering in 4 Dimensions