(sinx)=cosx
(cosx)=-sinx
(tanx)=sec^2x
(cotx)=-csc^2x
(secx)=tanxsecx
(cscx)=-cotxcscx
a²=b^2+c^2-2·b·c·cosA
b^2=a^2+c^2-2·a·c·cosB
c^2=a^2+b^2-2·a·b·cosC
cosC=(a^2+b^2-c^2)/(2·a·b)
cosB=(a^2+c^2-b^2)/(2·a·c)
cosA=(c^2+b^2-a^2)/(2·b·c)
特殊的三角函数值汇总A0°30°45°60°90°120°135°150°180°270°A弧度0π/6π/4π/3π/22π/33π/45π/6π3π/2sinA01/2√2/2√3/21√3/2√2/21/20-1cosA1√3/2√2/21/20-1/2-√2/2-√3/2-10tanA0√3/31√3None-√3-1-√3/30NonecotANone√31√3/30-√3/3-1-√3None0