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1、和角差角：cos(a B )=cosa cos B 干 sin a sin B sin( a B )=sin a cos B cos a sin B tan( a B )=(tan a tan B )/(1 干 tan a tan B ) 二倍角公式：sin(2a )=2sin a cos a =2tanA2( a )/1+tanA2( a ) cos(2 a )=cosA2( a )昨和人2( a )=2cosA2( a )-1=1-2sinA2( a )=(1-tanA2( a )/(1+tanA2( a ) tan(2 a )=2tan a /1-tanA2( a )半角公式：sinA2
2、( a /2)=(1-cosa )/2cosA2( a /2)=(1+cosa )/2tanA2( a /2)=(1-cosa )/(1+cos a )tan( a /2)=sin a /(1+cos a )=(1-cosa )/sin a三倍角公式：sin3a =3sin a -4sinA3( a )cos3 a =4cosA3( a )-3C0S atan3 a =(3tan a -tanA3( a ) (1-3tanA2( a )sin3 a =4sin a x sin(60- a )sin(60+ a )cos3 a =4cos a X COS(60- a)COS(60+ a ) ta
3、n3 a =4tan a x tan(60- a )tan(60+ a ) 万能代换公式：半角的正弦、余弦和正切公式(降幂扩角公式)sin a =2tan( a /2)/1+tanA2( a /2)cos a =1-tanA2( a /2)/1+tanA2( a /2)tan a =2tan( a /2)/1-tanA2( a /2)积化和差公式：sin a cos B =(1/2)sin( a + B )+sin( a - B ) cos a sin B =(1/2)sin( a + B )-sin( a - B ) cos a cosB =(1/2)cos( a + B )+8S(a -
4、B ) sin a sin B =-(1/2)cos( a + B )-cos( a - B ) 和差化积公式：sin a +sin B =2sin( a + B )/2cos( a - B )/2sin a -sin B =2cos( a + B )/2sin( a - B )/2 cos a +cosB =2cos(a + B )/28S( a - B )/2 cos a -cos B =-2sin( a + B )/2sin( a - B )/2和角差角：cos(a B )=cosa cos B 干 sin a sin B sin( a B )=sin a cos B cos a sin
5、 B tan( a B )=(tan a tan B )/(1 干 tan a tan B ) 二倍角公式：sin(2a )=2sin a cos a =2tanA2( a )/1+tanA2( a ) cos(2 a )=cosA2( a )-SinA2( a )=2cosA2( a )-1=1-2sinA2( a )=(1-tanA2( a )/(1+tanA2( a ) tan(2 a )=2tan a /1-tanA2( a )半角公式：sinA2( a /2)=(1-cosa )/2cosA2( a /2)=(1+coSa )/2tanA2( a /2)=(1-cosa )/(1+c
6、os a )tan( a /2)=sin a /(1+cos a )=(1-coSa )/sin a三倍角公式：sin3a =3sin a -4sinA3( a )cos3 a =4cosA3( a )-3coS atan3 a =(3tan a -tanA3( a ) (1-3tanA2( a )sin3 a =4sin a x sin(60- a )sin(60+ a )cos3 a =4cos a X cos(60- a)COS(60+ a ) tan3 a =4tan a x tan(60- a )tan(60+ a ) 万能代换公式：半角的正弦、余弦和正切公式(降幂扩角公式)sin
7、a =2tan( a /2)/1+tanA2( a /2)cos a =1-tanA2( a /2)/1+tanA2( a /2)tan a =2tan( a /2)/1-tanA2( a /2)积化和差公式：sin a cos B =(1/2)sin( a + B )+sin( a - B ) cos a sin B =(1/2)sin( a + B )-sin( a - B ) cos a cos B =(1/2)cos( a +B )+8S( a - B ) sin a sin B =-(1/2)cos( a +B )-cos(a - B ) 和差化积公式：sin a +sin B =2
8、sin( a + B )/2cos( a - B )/2 sin a -sin B =2cos( a + B )/2sin( a - B )/2 cos a +cosB =2cos( a + B )/2cos( a - B )/2 cos a -cos B =-2sin( a + B )/2sin( a - B )/2和角差角：cos(a B )=cosa cosB 干 sin a sin B sin( a B )=sin a cos B cos a sin B tan( a B )=(tan a tan B )/(1 干 tan a tan B ) 二倍角公式：sin(2 a )=2sin
9、a cos a =2tanA2( a )/1+tanA2( a ) cos(2 a )=cosA2( a )-SinA2( a )=2cosA2( a )-1=1-2sinA2( a )=(1-tanA2( a )/(1+tanA2( a ) tan(2 a )=2tan a /1-tanA2( a )半角公式：sinA2( a/2)=(1-cosa )/2cosA2( a /2)=(1+coSa )/2tanA2( a /2)=(1-cosa )/(1+cos a )tan( a /2)=sin a /(1+cos a )=(1-cos a )/sin a三倍角公式：sin3 a =3sin
10、 a -4sinA3( a )cos3 a =4cosA3( a )-3coS atan3 a =(3tan a -tanA3( a ) (1-3tanA2( a )sin3 a =4sin a x sin(60- a )sin(60+ a )cos3 a =4cos a x cos(60- a)COS(60+ a ) tan3 a =4tan a x tan(60- a )tan(60+ a ) 万能代换公式：半角的正弦、余弦和正切公式(降幂扩角公式)sin a =2tan( a /2)/1+tanA2( a /2)cos a =1-tanA2( a /2)/1+tanA2( a /2)ta
11、n a =2tan( a /2)/1-tanA2( a /2)积化和差公式：sin a cos B =(1/2)sin( a + B )+sin( a - B ) cos a sin B =(1/2)sin( a + B )-sin( a - B ) cos a cos B =(1/2)cos( a +B )+Cos( a - B ) sin a sin B =-(1/2)cos( a +B )-cos(a - B ) 和差化积公式：sin a +sin B =2sin( a + B )/2cos( a - B )/2 sin a -sin B =2cos( a + B )/2sin( a -
12、 B )/2 cos a +CosB =2cos( a + B )/2cos( a - B )/2 cos a -cos B =-2sin( a + B )/2sin( a - B )/2和角差角：cos(a B )=cosa cosB 干 sin a sin B sin( a B )=sin a cos B cos a sin B tan( a B )=(tan a tan B )/(1 干 tan a tan B ) 二倍角公式：sin(2 a )=2sin a cos a =2tanA2( a )/1+tanA2( a ) cos(2 a )=CosA2( a )-SinA2( a )=2cosA2( a )-1=1-2sinA2( a )=(1-tanA2( a )/(1+tanA2( a ) tan(2 a )=2tan a /1-tanA2( a )半角公式：sinA2( a/2)=(1-cosa )/2CosA2( a /2)=(1+CoSa )/2tanA2( a /2)=(1-cosa )/(1+cos a )tan( a /2)=sin a /(1+cos a )=(1-cos a )/sin a