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# Dividing Complex Numbers

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Divide (2+4i)  /  (−3+2i)

Answer in standard form for complex numbers.

I attempted this problem, but I'm not sure if it's right. If someone could possibly tell me what I did wrong, then I'd appreciate that. Thank you!

Here's my work:

(2+4i)  /  (-3+2i)   x   (-3+2i)  /  (-3+2i)

= (-6+4i-12+8i2)  /  (9-6i-6i+4i2

= (-6-8i+8i2)  /  (9-12i+4i2)

= (2i+8(-1))  /  (-3+3i+4(-1))

= (2i-8)  /  (-3+3i-4)

= (8-2i)  /  (-7+3i).

May 13, 2020

#1
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2/13-16/13i

that should be the final answer

hope this helped

May 13, 2020
#3
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Guest, when answering questions, it's good practice to include work so the asker won't be like "what the wha"

:)

hugomimihu  May 13, 2020
#2
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Wellllll

Keep in mind that a+b * a-b = a^2 -b^2

So you should actually multiply by

(2+4i)  /  (-3+2i)   x   (-3-2i)  /  (-3-2i)

And try this out!

I haven't done complex numbrs for a few weeks so I'm kinda rusty.

I'm pretty sure this should work.

I haven't tried it out but I'm reasonably sure that it should work

Update me on any progress!

If you don't understand anything feel free to ask.

May 13, 2020
#4
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Yeah ! If you look at my work, then I did that. I'm just not sure if it's right. That's the only problem. :)

auxiarc  May 13, 2020
#5
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Haha

No, I meant -3 MINUS 2i, not plus.

You wrote  (-3+2i)  /  (-3+2i) this

hugomimihu  May 13, 2020
#6
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Ohhh! Okay, my bad. I will try that. :)

auxiarc  May 13, 2020
#7
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I believe it should remove the complex number from the denominator and make it un-complex

hugomimihu  May 13, 2020
#10
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I got

(2+4i)  /  (-3+2i)   x   (-3+2i)  /  (-3+2i)

= (-6-4i-12i-8i2)  /  (9+6i-6i-4i2)

= (-6-16i-8i2)  /  (9-4i2)

= (-6-16i-8(-1))  /  (9-4(-1))

= (-6-16i+8)  /  (9+4)

= (2-16i)  /  (13)        OR       2 / 13   x   -16i / 13

auxiarc  May 13, 2020
#11
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Great job!

hugomimihu  May 13, 2020
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(2 + 4i)  / (-3 + 2i)      multiply num/den  by  the conjugate of -3 + 2i  =  -3 - 2i

So we have

(2 + 4i) ( -3 - 2i)

_____________   =

(-3 + 2i) (-3 - 2i)

-6 - 12i - 4i - 8i^2

_______________  =

9 + 6i - 6i - 4i^2

-6 - 16i + 8

________   =

9 - 4(-1)

2 - 16i

_________  =

9 +  4

(2/13) - (16/13) i

May 13, 2020
#9
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Oh Melody's not going to be happy with you

"I'd prefer if you gave hints and not full answers"

LOL

hugomimihu  May 13, 2020
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Oh, omigosh! Thank you so much! I see where I went wrong. I tried it for myself and also got the same answer! I appreciate your time and your help:)

auxiarc  May 13, 2020
#13
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HAHAHA!!!!!....it wouldn't be the first time that Melody was unhappy with me   !!!

And THX, auxiarc   !!!!

CPhill  May 13, 2020