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: Evaluate: RonL
Originally Posted by CaptainBlack You question is: Evaluate: RonL 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 . RonL
Hint: You can do the second integral with a simple substitution. So let's look at the first term: Let Thus Does this integral look familiar? -Dan
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... -Dan
Hi Dan, 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 Also, Can anyone remind me how to do the trig substitution? I forgot it ! Please show me the steps . Thanks.
Last edited by kittycat; Aug 17th 2007 at 02:23 PM.
Set Now when you have all integrated you use the first substitution to turn the trig. expressions into expressions.
hi Krizalid, 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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