逍遥学能 2016-09-24 15:36
精选2016中考理科数学公式
两角和与差的三角函数: sin(A+B) = sinAcosB+cosAsinB
sin(A-B) = sinAcosB-cosAsinB ?
cos(A+B) = cosAcosB-sinAsinB
cos(A-B) = cosAcosB+sinAsinB
tan(A+B) = (tanA+tanB)/(1-tanAtanB)
tan(A-B) = (tanA-tanB)/(1+tanAtanB)
cot(A+B) = (cotAcotB-1)/(cotB+cotA)
cot(A-B) = (cotAcotB+1)/(cotB-cotA)
三角和的三角函数:
sin(++)=sincoscos+cossincos+coscossin-sinsinsin
cos(++)=coscoscos-cossinsin-sincossin-sinsincos
tan(++)=(tan+tan+tan-tantantan)/(1-tantan-tantan-tantan)
辅助角公式:
Asin+Bcos=(A^2+B^2)^(1/2)sin(+t),其中
sint=B/(A^2+B^2)^(1/2)
cost=A/(A^2+B^2)^(1/2)
tant=B/A
Asin+Bcos=(A^2+B^2)^(1/2)cos(-t),tant=A/B
倍角公式:
sin(2)=2sincos=2/(tan+cot)
cos(2)=cos^2()-sin^2()=2cos^2()-1=1-2sin^2()
tan(2)=2tan/[1-tan^2()]
三倍角公式:
sin(3)=3sin-4sin^3()
cos(3)=4cos^3()-3cos
半角公式:
sin(/2)=((1-cos)/2)
cos(/2)=((1+cos)/2)
tan(/2)=((1-cos)/(1+cos))=sin/(1+cos)=(1-cos)/sin
降幂公式
sin^2()=(1-cos(2))/2=versin(2)/2
cos^2()=(1+cos(2))/2=covers(2)/2
tan^2()=(1-cos(2))/(1+cos(2))
万能公式:精选2016中考理科数学公式
sin=2tan(/2)/[1+tan^2(/2)]
cos=[1-tan^2(/2)]/[1+tan^2(/2)]
tan=2tan(/2)/[1-tan^2(/2)]
积化和差公式:
sincos=(1/2)[sin(+)+sin(-)]
cossin=(1/2)[sin(+)-sin(-)]
coscos=(1/2)[cos(+)+cos(-)]
sinsin=-(1/2)[cos(+)-cos(-)]
和差化积公式:
sin+sin=2sin[(+)/2]cos[(-)/2]
sin-sin=2cos[(+)/2]sin[(-)/2]
cos+cos=2cos[(+)/2]cos[(-)/2]
cos-cos=-2sin[(+)/2]sin[(-)/2]
推导公式
tan+cot=2/sin2
tan-cot=-2cot2
1+cos2=2cos^2
1-cos2=2sin^2
1+sin=(sin/2+cos/2)^2
其他:
sin+sin(+2/n)+sin(+2*2/n)+sin(+2*3/n)++sin[+2*(n-1)/n]=0
cos+cos(+2/n)+cos(+2*2/n)+cos(+2*3/n)++cos[+2*(n-1)/n]=0 以及
sin^2()+sin^2(-2/3)+sin^2(+2/3)=3/2
tanAtanBtan(A+B)+tanA+tanB-tan(A+B)=0