Mathematics
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OpenStudy (anonymous):
here are the first four terms of an arithmetic sequence
10 16 22 28
what is the 10th term of this sequence? is it 64?
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jimthompson5910 (jim_thompson5910):
You got it, the nth term is 6n+4, so the tenth term is 6(10)+4 = 60+4 =64
OpenStudy (anonymous):
yay:D
OpenStudy (anonymous):
also\[3\sqrt{7}\] how do i rationalise the denominator?
jimthompson5910 (jim_thompson5910):
Is that the whole fraction?
OpenStudy (anonymous):
its 3 over then |dw:1339356855249:dw|
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jimthompson5910 (jim_thompson5910):
ah gotcha
jimthompson5910 (jim_thompson5910):
multiply top and bottom by the denominator sqrt(7) to rationalize this
jimthompson5910 (jim_thompson5910):
\[\Large \frac{3}{\sqrt{7}}\]
\[\Large \frac{3\sqrt{7}}{\sqrt{7}*\sqrt{7}}\]
OpenStudy (anonymous):
i seeeee is that all of it?
jimthompson5910 (jim_thompson5910):
no, there's more, you have to multiply the two sqrt(7) terms in the bottom, what do you get when you do that?
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OpenStudy (anonymous):
i swear you still end up with 7 though?
jimthompson5910 (jim_thompson5910):
yes you do, since sqrt(7)*sqrt(7) =sqrt(7*7) = sqrt(49) = 7
jimthompson5910 (jim_thompson5910):
So the final answer is \[\Large \frac{3\sqrt{7}}{7}\]
OpenStudy (anonymous):
will it always be that with every equation?
jimthompson5910 (jim_thompson5910):
what do you mean
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OpenStudy (anonymous):
|dw:1339357466179:dw|
jimthompson5910 (jim_thompson5910):
Do the same thing, but now multiply top and bottom by sqrt(8)
OpenStudy (anonymous):
|dw:1339357532573:dw|