// 実数\(\alpha\)，\(\beta\)，\(\gamma\) が，\(\displaystyle 0 < \alpha < \frac{\pi}{2}\)，\(\displaystyle 0 < \beta < \frac{\pi}{2}\)，\(\displaystyle 0 < \gamma < \frac{\pi}{2}\)，\(\displaystyle \alpha + \beta + \gamma = \frac{\pi}{2}\)…