Calculate Limit of 3/ (x (ln (x+4) - ln (x)) as x→∞

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Homework Statement



3/ (x (ln (x+4) - ln (x))

as x goes to infinity.

so first i look at this i i thought its going to 0 cause x is going to get larger at the bottom.

but then i see that the equation looks more like 3 / (x( ln ((x+1)/x))
ln ((x+1)/x) is going to 1. so that mean that ln 1= 0

so...
3 / x(0) = infinty?
 
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Nope, not infinity.

Hint: ln(a) - ln(b) = ln(a/b) and (1 + a/x)x → ea as x → ∞
 
it doesn't go to zero?
 
No. The limit is a positive number.
 
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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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