和差公式
sum and difference formulas Formulas that express the trigonometric functions of the sum or difference of two angles, e.g., $\sin(\alpha \pm \beta) = \sin\alpha
CSCA 数学 考试术语
sum and difference formulas Formulas that express the trigonometric functions of the sum or difference of two angles, e.g., $\sin(\alpha \pm \beta) = \sin\alpha
CSCA 数学 考试术语