kingBook

ÕªÒª£º Á½½ÇºÍÓë²îµÄÕýÏÒ¡¢ÓàÏÒ¡¢ÕýÇй«Ê½£º \(\cos (\alpha \pm \beta ) = \cos a\cos \beta \mp\sin \alpha \sin \beta\) \(\sin (\alpha \pm \beta ) = \sin \alpha \cos \beta \pm \c ÔĶÁÈ«ÎÄ

ÕªÒª£º https://baike.baidu.com/item/%E4%B8%89%E8%A7%92%E5%87%BD%E6%95%B0%E5%85%AC%E5%BC%8F/4374733 ¹«Ê½¶þ $\sin (\pi+\alpha ) = -\sin a$ $\cos (\pi+a) = -\cos a ÔĶÁÈ«ÎÄ

ÕªÒª£º \(\sin^{2}\alpha + \cos^{2}\alpha = 1\) \(\frac{\sin a}{\cos a} = \tan a\) ÔĶÁÈ«ÎÄ