precalc
posted by kim .
express the complex number in standard form(that is like a+bi)
1/2+i
2+i/2i

rationalize the denominator. I will do one:
(2+i)/(2i)= 2+i)(2+i)/(2i)(2+i)=
(2+i)^2/(2i^2)= (4+4i+i^2)/3
you can complete it. 
so is that the final answer

os is the final answer 8i+i^3/3

(2+i)/(2i)
=(2+i)(2+i)/((2+i)(2i))
=(4+4i+i²)/(2²i²)
=(4+4i1)/(4(1))
=(3+4i)/5
You can proceed along the same lines for the first problem.