## anonymous 5 years ago Help me once again please: 3+5i ----- 1-2i

1. dumbcow

what are we solving for?

2. anonymous

um question is "Evaluate the following"

3. anonymous

its that thing where i^1 = i i^2 = -1 i^3 = -i i^4 = 1

4. dumbcow

you could multiply by conjugate to get rid of i in the denominator $\frac{(3+5i)(1+2i)}{(1-2i)(1+2i)}$

5. anonymous

then expand? the problem and solve correct?

6. dumbcow

yes you should get (11i -7)/5

7. anonymous

i got the 11i-5 but where does the /5 come from?

8. dumbcow

when you multiply the bottom 1 -2i +2i -4i^2 1-4i^2 1-4(-1) 1+4 5

9. anonymous

Oh so multiplying both top and bottom doesn't cancel out the bottom. I see where i missed up, thank you very much :)