一つ上へ

\begin{align} \dfrac{1}{ABC} &= 2\int^{1}_{0}dx \int^{1}_{0}dy \dfrac{x}{[(1-x)A + xyB + x(1-y)C]]^{3}} \\ \dfrac{1}{ABCD} &= 6\int^{1}_{0}dx \int^{1}_{0}dy \int^{1}_{0}dz \dfrac{x^{2}y}{[(1-x)A + x(1-y)B + xyzC + xy(1-z)D]^{4}} \end{align}