Those things scare me.(adsbygoogle = window.adsbygoogle || []).push({});

A lot.

They look tame and not so im-proper when you only evaluate the integral and take the limit.... then you see that section in your texts titled " Comparison of improper integrals."

I've looked at a few google links but all problems still seem so different to me-- I can't pin down a pattern I can use. I know about the comparison test ( 0 <= f(x) <= g(x) ) for example but applying it is kinda.. hard.

I know I'll be able to do HW but I don't know if I'll master the subject to do a problem like this for example:

Find the value of a (to three decimal places) that makes

[tex]\int a e^u dx = 1[/tex]

limits are negative infinity to positive infinity...

btw there is no "u" in the problem... I can't use this tex thing properly so here u is = -x^2/2 that's the negative of the square root of x over 2...

Now how do I even start such a problem? My plan of attack:

take outaoutside and break the integral into two parts (with limits as negative infinity to b for the first integral and b to infinity for the second integral) and evaluate the limits... I'm guessing it converges. I'll set that value it coverges to equal to 1 and solve for anathat will somehow transform that value to 1...

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# Homework Help: Any tips on improper integrals? (also, question)

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