See complex number, quaternion.
A unit vector, usually in the direction of the x‐axis.
A symbol used to represent √−1. It is an imaginary number, which is distinguished from real numbers. Engineers tend to use the symbol j instead of i. See complex numbers.
科学参考收录了60776条科技类词条，基本涵盖了常见科技类参考文献及英语词汇的翻译，是科学学习和研究的有利工具。