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The following identity may be regarded as a formulation of the
Weierstrass product for the Gamma function.
\[ \int_{0}^{\infty} t^x e^{-t} \frac{dt}{t} \int:
   = \frac{1}{x}
     \prod_{k=1}^{\infty}
       \frac{\bal{1 + \frac{1}{k}}^x}{\bal{1 + \frac{x}{k}}}
     \prod: \]
Understanding the derivation of this identity is reasonable for
a bright student of first year undergraduate calculus in the
United States.

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