Сравни

1. \(\sin \dfrac{13\pi}{7}\) и \(\sin \dfrac{15\pi}{8}\) ;

2. \(\cos (-8)\) и \(\cos (-9)\) .

Ответ: 1) [ \(\gt\) | \(\lt\) | \(=\) ]; 2) [ \(\gt\) | \(\lt\) | \(=\) ].