+0  
 
0
249
1
avatar
(4+1i) * (3-5i)

It says that becomes 17 - 17i

but how's that possible?

Isn't it like this

(4+1i) * (3-5i)
4 * 3 = 12
4 * (-5i) = -20i
1i * 3 = 3i
1i * (-5i) = -5i

So I get it to

12 - 20i + 3i - 5i = 12 - 18i

Any help is very much appreciated, thanks.
Guest Apr 18, 2012
 #1
avatar+3076 
0
[input](4+1i) * (3-5i)[/input]

here is the problem: "1i * (-5i) = -5i"

(4+1i) * (3-5i)
4*3-4*5i+1i*3-(5i*1i)
12-20i+3i-(5i^2)
12-20i+3i-(-5)
12-20i+3i+5
17-17i
admin  Apr 18, 2012

14 Online Users

avatar

New Privacy Policy

We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive information about your use of our website.
For more information: our cookie policy and privacy policy.