What it means
The number whose square is −1. Every complex number is a + bi for real a and b. Electrical engineers write j instead, because i is the current.
Read aloud in real formulas
i² = −1
Aethel says
i squared equals negative 1
the definition of i
e^(iπ) + 1 = 0
Aethel says
e to the power of i pi, plus 1 equals 0
Euler's identity
Typing it
- LaTeX
- i
- Unicode
- —
Formulas that use it
Questions
How do you say i out loud?
It is usually read “i”.
What does i mean in maths?
The number whose square is −1. Every complex number is a + bi for real a and b. Electrical engineers write j instead, because i is the current.
How do you type i?
In LaTeX, write i.