两角和公式
sin(A+B) = sinAcosplayB+cosplayAsinB
sin(A-B) = sinAcosplayB-cosplayAsinB
cosplay(A+B) = cosplayAcosplayB-sinAsinB
cosplay(A-B) = cosplayAcosplayB+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)
倍角公式
tan2A = 2tanA/(1-tan^2 A)
Sin2A=2SinA?cosplayA
cosplay2A = cosplay^2 A--Sin^2 A
=2cosplay^2 A1
=12sin^2 A
三倍角公式
sin3A = 3sinA-4(sinA)^3;
cosplay3A = 4(cosplayA)^3 -3cosplayA
tan3a = tan a ? tan(/3+a)? tan(/3-a)
半角公式
sin(A/2) = {(1--cosplayA)/2}
cosplay(A/2) = {(1+cosplayA)/2}
tan(A/2) = {(1--cosplayA)/(1+cosplayA)}
cot(A/2) = {(1+cosplayA)/(1-cosplayA)} ?
tan(A/2) = (1--cosplayA)/sinA=sinA/(1+cosplayA)
和差化积
sin(a)+sin(b) = 2sin[(a+b)/2]cosplay[(a-b)/2]
sin(a)-sin(b) = 2cosplay[(a+b)/2]sin[(a-b)/2]
cosplay(a)+cosplay(b) = 2cosplay[(a+b)/2]cosplay[(a-b)/2]
cosplay(a)-cosplay(b) = -2sin[(a+b)/2]sin[(a-b)/2]
tanA+tanB=sin(A+B)/cosplayAcosplayB
积化和差
sin(a)sin(b) = -1/2*[cosplay(a+b)-cosplay(a-b)]
cosplay(a)cosplay(b) = 1/2*[cosplay(a+b)+cosplay(a-b)]
sin(a)cosplay(b) = 1/2*[sin(a+b)+sin(a-b)]
cosplay(a)sin(b) = 1/2*[sin(a+b)-sin(a-b)]
诱导公式
sin(-a) = -sin(a)
cosplay(-a) = cosplay(a)
sin(/2-a) = cosplay(a)
cosplay(/2-a) = sin(a)
sin(/2+a) = cosplay(a)
cosplay(/2+a) = -sin(a)
sin(-a) = sin(a)
cosplay(-a) = -cosplay(a)
sin(+a) = -sin(a)
cosplay(+a) = -cosplay(a)
tgA=tanA = sinA/cosplayA
万能公式
sin(a) = [2tan(a/2)] / {1+[tan(a/2)]^2}
cosplay(a) = {1-[tan(a/2)]^2} / {1+[tan(a/2)]^2}
tan(a) = [2tan(a/2)]/{1-[tan(a/2)]^2}
其它公式
a?sin(a)+b?cosplay(a) = [(a^2+b^2)]*sin(a+c) [其中，tan(c)=b/a]
a?sin(a)-b?cosplay(a) = [(a^2+b^2)]*cosplay(a-c) [其中，tan(c)=a/b]
1+sin(a) = [sin(a/2)+cosplay(a/2)]^2;
1-sin(a) = [sin(a/2)-cosplay(a/2)]^2;;
其他非重点三角函数
csc(a) = 1/sin(a)
sec(a) = 1/cosplay(a)
