倒数关系:

$sin\alpha cos\alpha=1$

$cos\alpha sec\alpha = 1$

$tan\alpha cot\alpha = 1$

商数关系：

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

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

平方关系：

$sin^2\alpha + cos^2\alpha = 1$

$1 + tan^2\alpha = sec^2\alpha$

$1 + cot^2\alpha = csc^2\alpha$