Mathematics
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OpenStudy (anonymous):
How would i rationalize 6/ 3+i
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OpenStudy (anonymous):
multiply by the conjugate
OpenStudy (anonymous):
multiply by 1 using the conjugate*
OpenStudy (anonymous):
* top n bottom by 3-i
OpenStudy (anonymous):
So 9i?
OpenStudy (anonymous):
6(3-i) / (3+i)(3-i)
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OpenStudy (anonymous):
Is that all that I have to do? I'm not really sure how to do these sorts of problems
OpenStudy (anonymous):
You need to multiply out the brackets and simplify if possible
OpenStudy (anonymous):
Just like normal except you have i's to deal with...
OpenStudy (anonymous):
6(3-i)? Wouldn't the bottom cancel itself out?
OpenStudy (anonymous):
It is a kind of trick to get rid of the i on the bottom.....
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OpenStudy (anonymous):
Similar to how you get rid of a rdical, same sort of idea...
OpenStudy (anonymous):
So confused
OpenStudy (anonymous):
Multiply it out and you will see...
OpenStudy (anonymous):
9-i/9
OpenStudy (anonymous):
which you could divide 9 by 9 to get one, so -i?
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OpenStudy (anonymous):
6(3-i) is 18-6i
Where do you get 9-i from?
OpenStudy (anonymous):
Oh wow opps. haha I added.
OpenStudy (anonymous):
Ok, now what do you get for the bottom?
OpenStudy (anonymous):
9?
OpenStudy (anonymous):
You have (3+i)(3-i)
Tell me how it comes to 9
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OpenStudy (anonymous):
You multiply and the +i and -i cancel out? i'm really sorry, this is new to me haha
OpenStudy (anonymous):
(3+i)(3-i) is 3*3 + 3*i -3*i - i^2 (using FOIL?)
OpenStudy (anonymous):
So the 3i's cancel out and leave 9-i^2
So what is i^2 ?
OpenStudy (anonymous):
-1
OpenStudy (anonymous):
Right, so what is the bottom ( hint-it is not 9)
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OpenStudy (anonymous):
8?
OpenStudy (anonymous):
9-(-1)
OpenStudy (anonymous):
10
OpenStudy (anonymous):
Ok so finally you have 18-6i/10 which you can divide by 2 to get
9-3i/5 as a final answer.
OpenStudy (anonymous):
So, procedure for these is *by conjugate top and bottom then simplify
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OpenStudy (anonymous):
thank you so much!!!
OpenStudy (anonymous):
ur welcome