Why is it that if you multiply a negative imaginary number (-i) by a positive imaginary number (i), it equals to positive 1? Shouldn’t it be a negative 1? -(-1) • (-1) = -1 This is the right equation, right?

Accepted Solution

Hi there!

Unfortunately, that's not the right equation. I'll help show you the proper steps.

So, first, let's define i.

i = √(-1)

Now, let's multiply -i and i


Substitute the value of i

- √(-1) * √(-1)

Let's add a parenthesis using the associative property of multiplication

- [ √(-1) * √(-1) ]

Multiplying two same square roots eliminates the square root symbol.

- (-1)

A negative of a negative is positive

= 1

Thus, a negative imaginary number multiplied with a positive imaginary number equals positive 1.

Have an awesome day! :)