Mathematics
8 Online
OpenStudy (anonymous):
Find the length of the curve: y = 1+2x^(3/2)
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OpenStudy (anonymous):
\[0 \le x \le 1\]
OpenStudy (anonymous):
L = \[\int\limits_{0}^{1} \sqrt{1 + \frac{ dy }{ dx }}^{2} dx\]
OpenStudy (anonymous):
^yep
OpenStudy (anonymous):
2.268 would be the length when you integrate from 0 to 1
OpenStudy (anonymous):
Well, I to L = \[\int\limits_{0}^{1}\sqrt{1+(3x ^{1/2})}\] And I'm stuck there now
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OpenStudy (anonymous):
it'll be sqrt(1+3x)
OpenStudy (anonymous):
So you are integrating from 0 to 1 of sqrt(1+9x). you can get this if you simplify the equation.
OpenStudy (anonymous):
it'll be sqrt(1+9x)
OpenStudy (anonymous):
substitute (1+9x)= t^2
OpenStudy (anonymous):
does it help u?
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OpenStudy (anonymous):
I'm not sure how you get from sqrt(1+3x^(1/2)) to 1+9x
OpenStudy (anonymous):
Its 3x^(3/2)
OpenStudy (anonymous):
actually it's integral of sqrt( 1+ (dy/dx)^2)
OpenStudy (anonymous):
OH I forgot about the square
OpenStudy (anonymous):
and dy/dx= 3 sqrt(x)
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OpenStudy (anonymous):
When you square both sides you get the equation that I wrote above
OpenStudy (anonymous):
Okay, I have L = \[\int\limits_{0}^{1} \sqrt{1+9x}dx\]
OpenStudy (anonymous):
yes...now substitute 1+9x= t^2
OpenStudy (anonymous):
or u can write directly the integral of (1+9x)^1/2 = {(1+9x)^(1/2+1)}/9
OpenStudy (anonymous):
if u do the substitution then u'll have to change the limit of integration also.
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OpenStudy (anonymous):
so now u can solve by ur own?