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高中数学三角函数公式表

时间:2026-03-20 19:27:55

高中三角函数公式表如下:

基本关系式

$\tan\alpha \cdot \cot\alpha = 1$

$\sin\alpha \cdot \csc\alpha = 1$

$\cos\alpha \cdot \sec\alpha = 1$

$\frac{\sin\alpha}{\cos\alpha} = \tan\alpha = \frac{\sec\alpha}{\csc\alpha}$

$\frac{\cos\alpha}{\sin\alpha} = \cot\alpha = \frac{\csc\alpha}{\sec\alpha}$

倍角公式

$\sin 2A = 2\sin A \cos A$

$\cos 2A = \cos^2 A - \sin^2 A = 1 - 2\sin^2 A = 2\cos^2 A - 1$

$\tan 2A = \frac{2\tan A}{1 - \tan^2 A}$

和差角公式

$\sin(A + B) = \sin A \cos B + \cos A \sin B$

$\sin(A - B) = \sin A \cos B - \cos A \sin B$

$\cos(A + B) = \cos A \cos B - \sin A \sin B$

$\cos(A - B) = \cos A \cos B + \sin A \sin B$

$\tan(A + B) = \frac{\tan A + \tan B}{1 - \tan A \tan B}$

$\tan(A - B) = \frac{\tan A - \tan B}{1 + \tan A \tan B}$

$\cot(A + B) = \frac{\cot A \cot B - 1}{\cot B + \cot A}$

$\cot(A - B) = \frac{\cot A \cot B + 1}{\cot B - \cot A}$

辅助角公式

$\sin(A + B) = \sin A \cos B + \cos A \sin B = \sqrt{2} \sin\left(A + \frac{\pi}{4}\right)$

$\cos(A + B) = \cos A \cos B - \sin A \sin B = \sqrt{2} \cos\left(A + \frac{\pi}{4}\right)$

$\tan(A + B) = \frac{\tan A + \tan B}{1 - \tan A \tan B} = \frac{\sin A \cos B + \cos A \sin B}{\cos A \cos B - \sin A \sin B} = \frac{\tan A + \tan B}{1 - \frac{\sin A \sin B}{\cos A \cos B}} = \frac{\tan A + \tan B}{\frac{\cos A \cos B - \sin A \sin B}{\cos A \cos B}} = \frac{\tan A + \tan B}{\frac{1}{\tan\left(A + \frac{\pi}{4}\right)}}$

倍角公式推导

$\sin 3A = 3\sin A - 4\sin^3 A$

$\cos 3A = 4\cos^3 A - 3\cos A$

$\tan 3A = \tan A \tan(2A + A) = \frac{\tan A (2\tan A + \tan A)}{1 - \tan^2 A (2\tan A + \tan A)} = \frac{3\tan A - \tan^3 A}{1 - 3\tan^2 A}$

降幂公式

$\sin^2 A = \frac{1 - \cos 2A}{2}$

$\cos^2 A = \frac{1 + \cos 2A}{2}$

$\tan^2 A = \frac{\sin^2 A}{\cos^2 A} = \frac{1 - \cos^2 A}{\cos^2 A} = \frac{1}{\cos^2 A} - 1$

这些公式涵盖了高中三角函数的基本关系、倍角公式、和差角公式、辅助角公式、倍角公式推导以及降幂公式。掌握这些公式有助于解决涉及三角函数的数学问题。