2 times the integral (from -3 to 3) of (4-x) (sqrt(9-x^2) ) dx.
Thank you very much.
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Originally Posted by kittycat 2 times the integral (from -3 to 3) of (4-x) (sqrt(9-x^2) ) dx.
Thank you very much. You question is:
Originally Posted by CaptainBlack You question is:
and these two integrals can be done by the usual book methods, the first by a trig substitution and the second
by looking at the derivative of .
You can do the second integral with a simple substitution. So let's look at the first term:
Does this integral look familiar?
Or from the beggining you can use a simple trig. sub. defined by
In general we have that
Originally Posted by Krizalid In general we have that I think you want to write (also mention that , just to be safe, write ).
Originally Posted by ThePerfectHacker I think you want to write (also mention that , just to be safe, write ). And mention that a is a real number, and...
how do I end this one?
9 times the integral from -1 to 1 of sqrt(1-y^2) dy - your last step! Really don't know how
Can anyone remind me how to do the trig substitution? I forgot it ! Please show me the steps . Thanks.
Last edited by kittycat; August 17th 2007 at 01:23 PM.
Now when you have all integrated you use the first substitution to turn the trig. expressions into expressions.
Please show me more ...! really forgot ! If possible , please show me the steps how to show the first integral by trig substitution. thank you very much.
Change of variables according to implies
Which is easy to take.
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