Simone
sin²巧拿高a+cos²a=1tana=sina/cossin(a+b)=sinacosb+sinbcosa 二倍角孝尺公式sin2a=2sinacosa,cos2a=cos²敏银a-sin²a tan2a=2tana/1-tan²asin(a-b)=sinacosb-sinbcosacos(a+b)=cosacosb-sinasinbcos(a-b)=cosacosb+sinasinbtan(a+b)=tana+tanb/1-tanatanbtan(a-b)=tana-tanb/1+tanatanb
