math help people lik really desperate!!
posted by annaiiz on .
ok i have to divide complex numbers:
question is: 12i+i^3/1+i
this is what i did:
12i+i(i)/1+i
12ii^2/1+i
12ii(1)/1+i
12i+i/1+i
13i/1+i*1i/1i
1i3i+3i^2/1i+ii^2
1i3i+3(1)/1i^2
1i3i3/1(1)
14i3/2
24i/2
my answer is 2i1
is that right?

Be more specific with parentheses. Does the 1+i divide into only the i^3 term? Or does it divide into 1  2i + i^3?

from what you showed in your work I will asssume you meant
(12i+i^3)/(1+i)
you messed up in your first line.
remember i^3 = i(i^2) = i(1) = i
so
(12i+i^3)/(1+i)
= (12i  i)/1+i)
= (13i)/(1+i)
now multiply top and bottom by 1i to get
(14i  3i^2)/(1  i^2)
= (44i)/2
= 2  2i