Angle θ In any right triangle, the ratio of the opposite side to the adjacent side corresponding to θ is called the tangent of angle θ. If θ is placed in a rectangular coordinate system, that is, tan θ = y/x. TanA= opposite side/adjacent side. Equivalent to the slope k of a straight line in a rectangular coordinate system.

Extended data:

I. Relevant formulas

tan a=sin a/cos a

tanα= 1/cotα

1. Let α be an arbitrary angle, and the values of the same trigonometric function with the same terminal angle are equal: tan(2kπ+α)=tanα.

2. Let α be an arbitrary angle, and the relationship between π+α and the trigonometric function value of α is tan(π+α)=tanα.

3. The relationship between arbitrary angle α and trigonometric function value of-α: tan (-α) =-tan α.

4. The relationship between π-α and the trigonometric function value of α can be obtained by Formula 2 and Formula 3: tan (π-α) =-tan α.

5. Using formula 1 and formula 3, we can get the relationship between the trigonometric function values of 2π-α and α: tan (2π-α) =-tan α.

Second, the inductive formula

tan(2kπ+α)=tan α

tan(π/2-α)=cot α

tan(π/2+α)=-cot α

tan(π+α)=tan α

tan(π-α)=-tan α