2 times the integral (from -3 to 3) of (4-x) (sqrt(9-x^2) ) dx. Thank you very much.
Follow Math Help Forum on Facebook and Google+
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; August 17th 2007 at 01:23 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.
View Tag Cloud