Exponential Convergence: Solving the Integral from 0 to Infinity of exp(-x)

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[SOLVED] exponential converge?

Homework Statement



does the integral from 0 to infinty of exp(-x) converge - if so, is it just accepted or does it need to proven?
 
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\int_0^{\infty}e^{-x}dx it is convergent and it needs to be proven!
you might want to go like this, although you haven't shown your work at all!

\lim_{b \rightarrow \infty} \int_0^{b}e^{-x}dx, now can you find an antiderivative for the integrand e^{-x}
 
thanks - yeah, sorry i havnt shown any working- i know it converegs to 1 though.
 
Mattofix said:
thanks - yeah, sorry i havnt shown any working- i know it converegs to 1 though.

Yeah after u evaluate that limit, you will end up with 1. good job!
 
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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