# Imaginary Numbers

Discussion in 'Computer Science & Culture' started by esp, Jan 26, 2002.

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1. ### espRegistered Senior Member

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908
I learned this a long time ago in college, but can't remember the specifics.

Can any of you assist my ailing memory and tell me what i or j terms are the applicable rules?

Examples would be useful.

3. ### James RJust this guy, you know?Staff Member

Messages:
38,035
A <b>complex</b> number is any number of the form:

x + iy

where i is the square root of negative one.

Here are some examples of arithmetic with complex numbers:

(-1 + 3i) + (7 - 2i) = 6 + i

(-1 + 3i) - (7 - 2i) = -8 + 5i

(-1 + 3i) &times; (7 - 2i)
= (-1 &times 7) + (-1 &times; -2i) + (3i &times; 7) + (3i &times; -2i)
= -7 + 2i + 21i -6i<sup>2</sup>
= -7 + 23i + 6
= -1 + 23i

Note that i<sup>2</sup> = -1, since i is the square root of -1.

5. Nothing to offend but is this Computer science forum?

anyways lets get back to what you asked.

as James has explained evry point,except one.

J.j is also the same.except for the fact that it is used in electrical engineering subjects for i,since <b>i</b> is current.anyway j is the same sqrt(-1) and it rotates the phase by 90 degree.

bye!