# complex numbers and imaginary units

posted by
**candace**
.

2i/1+i

your question probably says 'simplify'

multiply top and bottom by (1-i)\(1-i) and remember that i^2 =-1

so...

2i/(1+i) * (1-i)\(1-i)

= (2i - 2i^2)/(1-i^2)

= 2(i-i^2)/(1+1)

=i+1