Without LaTeX annotation:

Γ(t)=0+xt-1e-xdx=1tn=1(1+1n)t1+tn2πt(te)t

With LaTeX annotation:

Γ(t)=0+xt-1e-xdx=1tn=1(1+1n)t1+tn2πt(te)t{\Gamma(t)} = {\int_{0}^{+\infty} x^{t-1} e^{-x} dx} = {\frac{1}{t} \prod_{n=1}^\infty \frac{\left(1+\frac{1}{n}\right)^t}{1+\frac{t}{n}} } \sim {\sqrt{\frac{2\pi}{t}} \left(\frac{t}{e}\right)^t}