Question

How do you multiply `(1+i)(1-i)`?

Answer 1

Just as you would multiply any similar set of brackets: FOIL (first, outers, inners, lasts). In this case this totals 2.

Explanation:

Multiplying through using the FOIL approach:

`(1+i)(1-i) = (1*1) + (1*-i) + (i*1) + (i*-i)`
`= (1 + i - i -i^2)` but remember, since `i=sqrt(-1)`, `i^2=-1`.
`= 1+1 = 2`

in this case, the answer is a real number.