i是甚麼數?

i，它是 - 1的平方根，即i2 = - 1
複數為實數的推廣, 它使任一多項式都有根。 複數當中有個 「虛單位」---i。任一複數都可表達為x + iy，其中x及y皆為實數，稱為複數之「實部」(x)和「虛部」(iy)。

i是√(-1)
(a+bi)是複數

i is the complex number, but it is not the real number. The number i is such that i = Square Root of -1 (I don't know how to type the symbol) which is the same as saying i square = -1.We use i to simplify square roots of negative numbers.

2007-06-11 16:56:51 補充：
i = √-1 or i² = -1

因數,27的因數

代數-.-'