三角变换公式

sin(-α)= -sinα；cos(-α) = cosα；sin(π/2-α)= cosα；cos(π/2-α) =sinα；sin(π/2+α) = cosα；cos(π/2+α)= -sinα；sin(π-α) =sinα；cos(π-α) = -cosα；sin(π+α)= -sinα；cos(π+α) =-cosα；tanA= sinA/cosA；tan（π/2＋α）＝－c...