How would I work the integral: x^3 * sqrt(x^2 -9) dx without using trig substitution? My professor said that it is a way, but I don't see it!
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Originally Posted by latavee How would I work the integral: x^3 * sqrt(x^2 -9) dx without using trig substitution? My professor said that it is a way, but I don't see it! Split the integrand up , and then use integration by parts. CB
AH! Never thought of that! Thank you!
How about the substitution or equivalently ? Then and you end up with a polynomial in to integrate.
I would do by writing it as and using the substitution . Then du= 2xdx so and . That gives
I'm going to try some of these ideas out! and I will see if I can come up with the answer that I had using trig substitution/or nearly the same! Thanks guys!
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