Mathematics
14 Online
OpenStudy (thatonegirl_):
please help!! Integral using inverses
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OpenStudy (thatonegirl_):
\[\int\limits_{0}^{\sqrt{3}} \frac{ dx }{ \sqrt{4-x^2} }\]
OpenStudy (misty1212):
HI!!
OpenStudy (thatonegirl_):
Hello :D
OpenStudy (misty1212):
looks pretty much like an arcsine right?
OpenStudy (thatonegirl_):
yup!
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OpenStudy (misty1212):
in fact, if it was \[\int \frac{dx}{\sqrt{1-x^2}}\] it would be arcsine
OpenStudy (thatonegirl_):
mhm i'm having trouble trying to factor out the 4 :S
OpenStudy (misty1212):
\[4-x^2=4(1-\frac{1}{4}x^2)=4(1-(\frac{x}{2})^2\]
OpenStudy (thatonegirl_):
so would there be a sqrt over the 4?
satellite73 (satellite73):
yeah, that was just the algebra under the radical
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OpenStudy (mathmale):
Misty's presentation needs one more right parenthesis:
\[4-x^2=4(1-\frac{1}{4}x^2)=4(1-(\frac{x}{2})^2)\]
OpenStudy (thatonegirl_):
ah okay
OpenStudy (thatonegirl_):
so then u would just be x/2 ?
OpenStudy (misty1212):
the four will come out of the radical as a two
OpenStudy (misty1212):
yup, you can do a u - sub and change the limits of integration while you are at it
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OpenStudy (thatonegirl_):
ah okay i got it! That's mainly what was confusing me xD Thank you!!
OpenStudy (thatonegirl_):
I got pi/3 btw which i just put in and was right :)
OpenStudy (misty1212):
\[\color\magenta\heartsuit\]
OpenStudy (misty1212):
yay
OpenStudy (thatonegirl_):
Thank you!