Integral Problem: Integral of x((x-5)^11)dx

I mean, it's definitely possible that this was a mistake on your teacher's behalf. But, I, an anonymous stranger on the internet that knows neither you, nor your teacher, nor even what school you attend, cannot say with any degree of certainty. Only your teacher can say for certain. My best guess, however, is that it's a genuine problem. It's a bit ugly and has a lot of terms, but it's not excessively awful. When you get integrals that look deceptively simple like \(\displaystyle \displaystyle \int cos(x^2) \: dx\), whose solution actually involves a Fresnel Integral, or \(\displaystyle \displaystyle \int x! \: dx\), to which WolframAlpha says only "(no result found in terms of standard mathematical functions)," then you can suspect the exercise might be a typo ;)

Mostly, though, this problem is just busy work. Expanding out the \(\displaystyle (x - 5)^{11}\) term can be made a bit less tedious by using the Binomial Theorem and Pascal's Triangle, and then the lingering x out front increases the degree of the resulting polynomial by 1. When all is said and done, you'll have a 12th degree polynomial which can be broken up into 12 easy integrals via the sum rule.
 
I do not see any ridiculous process here,

u = x-5 → du = dx

\(\displaystyle \displaystyle{\int x * (x-5)^{11} dx}\)

\(\displaystyle = \ \displaystyle{\int (u+5) * u^{11} du}\)

and continue.....

So you're saying that the online calculator is wrong? Because if I continue the way you told me, I certainly won't get the ridiculous answer that I got from that calculator website.
 
So you're saying that the online calculator is wrong?
No, Subhotosh is saying that there's a different way to find that antiderivative (resulting in a factored form vs an expanded form).


Because if I continue the way you told me, I certainly won't get the ridiculous answer that I got from that calculator website.
You would, were you to expand the result.

In other words, there's more than one way to express the answer.

PS: The expanded form is a 13-degree polynomial; that's not ridiculous, itself. However, if you were instructed to report it on a timed test, then the exam question might be considered a bit ridiculous. :cool:
 
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