12-09-2003, 07:53 PM | #1 (permalink) |
Fledgling Dead Head
Location: Clarkson U.
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Calculus Question...
Evaluate the indefinate integral:
S (x+2)(x-7)^1/2 dx (note. If anyones qualified to help me, you shouldnt need to be told but... anything raised to the 1/2 is the same as sq. root. Also that s represents the integrand.) Should I be doing a "u-substitution"? Seemed like a good idea, but I cant seem to find anything to sub u in for, that makes du the rest of the problem. Any help would be greatly appreciated. |
12-09-2003, 09:02 PM | #2 (permalink) | |
I am Winter Born
Location: Alexandria, VA
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Are you taking the square root of everything or just the last term (x-7)? If it's just the last term, then your answer is:
Quote:
http://integrals.wolfram.com/ <-- Excellent website. Edit: To the best of my knowledge, you only use the "u substition method" (which, if memory serves, gives you Integral[ u dv ] = uv - Integral[ v du ] ) if you've got a term such as e^x or sin/cos values that do not naturally recycle themselves down to 0 under differentiation.
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12-09-2003, 09:31 PM | #4 (permalink) |
On the lam
Location: northern va
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S (x+2)(x-7)^1/2 dx
using integration by parts: d(uv) = udv + vdu implies that S u*dv = uv - S v*du. Now just figure out the variables... u = x + 2 du = dx v = (2/3) * (x-7)^1.5 dv = (x-7)^0.5*dx you should be able to figure it out from that.
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