Dividing complex numbers | Imaginary and complex numbers | Precalculus | Khan Academy
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- čas přidán 11. 07. 2011
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Dividing Complex Numbers
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I feel like I should be paying attention to the video and not the comments section...
But it's too late for that
When this says Precalculus but u're in Algebra 2
When you say you are in algebra 2 but I am in algebra 1 studying for the amc10
ikr
Lol I'm in 7th grade, so I think I'm supposed to be in prealgebra, but that's kinda a joke to me, so Precalculus is my level. I'm also doing well practicing for AMC10 papers, although I can't do 'em 'cause I live overseas.
when this says precalc but you're in Advanced Engineering Math and Analysis...
@@hasaniqbal233 that's more like it
Super helpful my lord...
men you are awesome you have no idea about the time you saved me....rushing for test!
YO!!! THANK YOU SO MUCH KHAN ACADEMY I FINALLY UNDERSTAND THIS!!!!
Thank you so so so very much! Now I will make a C, but not fail!! I just instantly calm down when I hear your voice because there are so many sketchy videos out there with random teachers trying to make money or whatever and who don't actually know what they are doing, so it's nice to actually learn something (especially if your teachers are useless).
Thanks for a very helpful explaination - in a non complex way.
I think I know the formula for the denominator multiplication u said. It is (a+b)(a-b) = a^2 - b^2
Wonderful! thank you so much for uploading! I Don't understand why ALEKS is so bad. Thank you for using color and being so upbeat! These videos have helped quickly and I appreciate that.
I always had a feeling math books had their flaws. My precalc book literally tells me that something like (5-7i)(5+7i) would be 5^2 - 7^2 but only in the denominator. It makes no sense
10/10 teaching there, book.
Its correct
The book is trying to teach you something of a shortcut, which is useful, but they don't explain how you get there like Khan Academy does, which is why it makes no sense. They've sort of left out parts and have said to you "Go figure" lol
Thank you sooo much I been struggling with slides I had to study from .
I am Back Now With Divide Version ITs So GOOD !
Thanks for Helping us !
This helped me a lot ❤️💖
I'm doing a programming assignment, basically gotta code a complex number calculator.
Abstracting the steps tells me to handle the top part the same way I handled regular multiplication, and to find the denominator for the real and imaginary parts, to do real^2 + imaginary +2 using the conjugate?
That's what 74 is, 49 + 25, and the real part was 7, the imaginary 5. It would be minus the imaginary if working with the original complex number although squaring it makes the sign stop being important it seems..
I guess I'll code it this way and then test if it gets the same results as an online calculator.
you are a live saver thx
because 3i x 5i = 15i squared
i squared = -1
so 15 x -1 = -15
where did you get i squared = -1 if we have no idea of what I equals to?
@@Drampam i=square root of -1
@@Drampam i is not a normal variable. Like @muhiya said, it is the square root of -1, which is unknown, hence why we let i represent its value.
very helpful!!
Thank you for the help
Sir, the denominator was of form (a+b)(a-b), you could have use the identity. Anyway thanx a lot sir it was helpful
Thank you
Thank you lord
Using the box makes things easier ^^.
thanks....
Thanks man
ohhhh. :D ty
thanks
Thanks
My teacher said me some formulas..Z1/Z2 the whole bar=Z1bar/Z2,Z2bar/Z1bar..can you explain this with example please...please
that's really
Soo how to express this in trigo and polar form??
Anyone in 2019?
how about 2023 ):
No, but how about in 2024 ;)
This isn't as hard as I thought is was.
ikr
question, how do you divide something like this?
(3 - 2i)^-1 / 2 + 2i
You have the answer yet?
U got the answer bro?
how about now?
Plus 51 over 74.
hey great comment! i laughed super hard! keep up the great work!
Any1 studying this in quarantine
5i x 5i should be 25i squared right? why it just 25 on the video?
That's because i squared is equal to -1, due to the definition of the imaginary number itself being equal to the square root of -1.
Therefore it becomes 25 * (i)^2, which is then the same as 25*(-1) or -25 as in the video. :-)
You're thinking of normal variables, "i" is a set number i=sqrt(-1) so think of it as 5(sqrt(-1))^2 which would equal -25. I think you are looking for dividing binomials.
When you keep repeating yourself, it makes me wonder if there's something wrong with the video on my side.
Why is it -15
2:08
3i*5i = -15
Yo will the imaginary number in the denominator always cancel out
What a...? How 3i * 5i goes to -15??? Why there is no square i any further in the equation?? Could someone explain, please?
i^2=-1 so -1 x 15=-15
Dont think of i as a normal variable, think of it as the square root of -1
sqrt(a) × sqrt(a) = a
so i² = -1
So 3i*5i = 15i² = -15
if you get 0 in the denominator of the answer, is it still considered undefined or is there some sort of special situation for complex numbers?
seanmxkid you won't get any zero, and by chance if you get one then your question ends right there by saying anything divided by by zero Is "not defined"😇
Watching this on the bus before exams lmao
On the bus to school?
So lucky you get to go to school. ugh I cant believe I just said that
@@endertobias1908 To be fair, that was a month ago, now I’m back in lockdown lol
Who's here from ms Maguires class?
Your voice is cracking
first
first reply
what about 2-i/-i? math is literally the worst