+0  
 
0
46
6
avatar+416 

Compute (1+i)(2+i)(3+i).

 

I know that i^2 is equal to -1. So i tried just solving it like that but its incorrect? I dont understand cuz 1+-1 equals 0 and since its multiplacation the answer theoreticly should equal 0 right?

 Apr 20, 2020
edited by AltShaka  Apr 20, 2020
 #1
avatar+55 
+1

Did you mean for it to be (2+1) or did you mean (2+i)? Clarify that please and then I'd be happy to help! smiley

 Apr 20, 2020
edited by Hi121529  Apr 20, 2020
 #2
avatar+416 
0

2+i srry

 Apr 20, 2020
 #3
avatar+14 
0

I got 6 + 12 i.

 Apr 20, 2020
 #4
avatar+416 
+1

Wait but its multiplacation..... So it should equal 0 right? Cuz i = Sqrt(-1)

 Apr 20, 2020
 #5
avatar+55 
+2

Okay so expanding (1+i)(2+i) we get

 

2+i+2i+i^2 = 

2+3i-1 = 

1+3i

 

Multiplying (1+3i)(3+i) we get

 

3+i+9i+3i^2 = 

3+10i+3(-1) =

10i

 

Hope that helps!

 Apr 20, 2020
edited by Hi121529  Apr 20, 2020
 #6
avatar+416 
+1

Wait Oh im so dumbbbb.. YAH I Solved it as i = -1...... Well looks like im kind of dumb.

 Apr 20, 2020

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