1. **State the problem:** Find the limit as $x \to \infty$ of
$$8e^{\sqrt{\frac{x}{x+1}}} \left(\frac{x-1}{x}\right)! - \left(8x^2 - 4x\ln x - \ln 2x - \frac{4x + 2\ln x}{\ln 2\pi}\right).$$
2. **Analyze the factorial term:** The term $\left(\frac{x-1}{x}\right)!$ is a factorial of a number approaching 1 from below as $x \to \infty$ because
$$\frac{x-1}{x} = 1 - \frac{1}{x} \to 1.$$
Factorials for non-integers are defined by the Gamma function:
$$n! = \Gamma(n+1).$$
So,
$$\left(\frac{x-1}{x}\right)! = \Gamma\left(\frac{x-1}{x} + 1\right) = \Gamma\left(2 - \frac{1}{x}\right).$$
As $x \to \infty$, this approaches $\Gamma(2) = 1! = 1$.
3. **Evaluate the exponential term:**
$$\sqrt{\frac{x}{x+1}} = \sqrt{1 - \frac{1}{x+1}} \to 1$$ as $x \to \infty$.
Thus,
$$e^{\sqrt{\frac{x}{x+1}}} \to e^1 = e.$$
4. **Combine the first term:**
$$8e^{\sqrt{\frac{x}{x+1}}} \left(\frac{x-1}{x}\right)! \to 8e \times 1 = 8e.$$
5. **Analyze the second term:**
$$8x^2 - 4x\ln x - \ln 2x - \frac{4x + 2\ln x}{\ln 2\pi}.$$
As $x \to \infty$, the dominant term is $8x^2$, which grows without bound.
6. **Conclusion:** The first term tends to a finite constant $8e$, but the second term grows like $8x^2$ which dominates and tends to infinity.
Therefore,
$$\lim_{x \to \infty} \left[8e^{\sqrt{\frac{x}{x+1}}} \left(\frac{x-1}{x}\right)! - \left(8x^2 - 4x\ln x - \ln 2x - \frac{4x + 2\ln x}{\ln 2\pi}\right)\right] = -\infty.$$
Limit Infinity 41Fc16
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