Integral: For What Values of p is Convergent?

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I got lost in an example in my book. Hoping someone could explain it to me.For what values of p is the intergral

from 1 to infinity \int \frac {1}{x^p}dx

convergent?

from 1 to infinity \int \frac {1}{x^p}dx

= lim (t -> infinity) \frac {x^-^p^+^1}{-p+1} (from x = 1 to x = t)

= lim (t -> infinity) \frac {1}{p-1} [\frac {1}{t^p^-^1} - 1]

the only thing that confuses me about this is how the t^p-1 ended up in the denominator because after the 2nd sept I get the following:

= lim (t -> infinity) \frac {t^p^-^1}{p-1} - \frac {1}{p-1}

Thanks!
 
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Isn't \int \frac{1}{x^{-p}}dx=\frac{x^{1+p}}{1+p}?
 
Oh, I'm sorry the intital inegral is

\int \frac {1}{x^p}dx

thanks for catching that mistake :)
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...

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