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Mathematics 14 Online
OpenStudy (anonymous):

Simplify

OpenStudy (anonymous):

OpenStudy (anonymous):

−1 − i −2 − i −1 + i −2 + i

OpenStudy (agent0smith):

Multiply the numerator and denominator by the conjugate of -2-2i... the conjugate of a+bi is: a-bi

OpenStudy (anonymous):

that's right!!!! thank youu

OpenStudy (agent0smith):

No prob :) let me know if you need more help!

OpenStudy (anonymous):

i got 4i over 0?

OpenStudy (agent0smith):

the conjugate is -2+2i...so \[\Large \frac{ 4 (-2+2i) }{ (-2-2i)(-2+2i) }\]

OpenStudy (anonymous):

okay, so you multiply the numerator and the denominator by the conjugate? but you don't change the negative sign to positive

OpenStudy (agent0smith):

Which negative? all you do is multiply both by the conjugate of -2-2i, which is -2+2i (the conjugate ONLY changes the sign of the imaginary part, not the real part)

OpenStudy (anonymous):

i'm doing something wrong here... ://

OpenStudy (anonymous):

the negative 2

OpenStudy (anonymous):

do i distribute 4 into -2 + 2i?

OpenStudy (agent0smith):

Yes, simplify the numerator and denominator both

OpenStudy (anonymous):

i got 6 for the numerator..?

OpenStudy (anonymous):

and -4..? eek

OpenStudy (agent0smith):

Their should be an i... show your work.

OpenStudy (agent0smith):

The denominator should be real, the numerator should have an i.

OpenStudy (anonymous):

so -8 + 2 (-1) i=(-1) as the numerator

OpenStudy (agent0smith):

\[\Large \frac{ 4 (-2+2i) }{ (-2-2i)(-2+2i) } =\frac{-8+8i }{ (-2-2i)(-2+2i) }\]

OpenStudy (agent0smith):

i is the square root of -1. i is not -1.

OpenStudy (anonymous):

got it. so how would you deal with the denominator

OpenStudy (agent0smith):

FOIL it/distribute it.

OpenStudy (agent0smith):

Same way you would with something like (x-2)(x+2). Remember that i*i = -1 (i^2 = -1)

OpenStudy (anonymous):

so... 4 + 2 -4i + 4i -4i

OpenStudy (anonymous):

whoops...! i mean 4 + 4i + 4i - 4i

OpenStudy (agent0smith):

That doesn't look right... \[\Large \frac{-8+8i }{ (-2-2i)(-2+2i) } = \frac{-8+8i }{4+4i-4i+4i^2 }\]

OpenStudy (anonymous):

crap.

OpenStudy (anonymous):

so then it would be.. -8 +8i / 4 + 4i

OpenStudy (agent0smith):

no, you're almost there... i^2 is -1.

OpenStudy (anonymous):

i mean i!!!

OpenStudy (anonymous):

so... -16/0 ?!?!?!

OpenStudy (agent0smith):

Oh wait, it was, i made a mistake \[\Large \frac{-8+8i }{ (-2-2i)(-2+2i) } = \frac{-8+8i }{4+4i-4i-4i^2 }\]

OpenStudy (agent0smith):

But how did you get -16... your i's keep disappearing...

OpenStudy (anonymous):

noo! how do i simplify that without multiplying each side by i, to get i^2 to then be -1..?

OpenStudy (agent0smith):

i^2 is equal to -1.

OpenStudy (agent0smith):

we have this. which we can simplify \[\Large \frac{-8+8i }{4+4i-4i-4i^2 }\] to \[\Large \frac{-8+8i }{4-4i^2 }\] and once more to \[\Large \frac{-8+8i }{4-4(-1) }\]

OpenStudy (anonymous):

thank you so much for taking the time to help me :) i'm so sorry my i's keep disappearing ://

OpenStudy (agent0smith):

Think of them as x's. They can't just disappear, unless it's an i^2 which is -1.

OpenStudy (anonymous):

got it! thank youu! so how about this... -8 + 8i / 8

OpenStudy (agent0smith):

Excellent! :) now you can still simplify a bit more...

OpenStudy (anonymous):

ahhhh :// i don't know what to do!!

OpenStudy (agent0smith):

Yes you do :P

OpenStudy (anonymous):

multiply each side by 8? then it would be -64 +8i ?

OpenStudy (anonymous):

that seems odd...hmm

OpenStudy (agent0smith):

No you just need to simplify... \[\Large \frac{ -8 + 8i }{ 8 } =\frac{ -8 }{ 8 }+\frac{ 8i }{ 8 }\]

OpenStudy (anonymous):

okay. alright. so 0i/8 ?

OpenStudy (anonymous):

i'm so lost :// so sorry

OpenStudy (agent0smith):

Just simplify each of those one at a time. What's -8/8? What's 8i/8?

OpenStudy (anonymous):

-1 + 1i ?

OpenStudy (agent0smith):

Excellent :)

OpenStudy (anonymous):

AHHHHH! thank you so so so so so SO much!!

OpenStudy (agent0smith):

haha you're welcome

OpenStudy (anonymous):

i wish i could give you a million medals!!

OpenStudy (agent0smith):

:D

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