1、sin 30 = 1/2、cos30 =√3/2、an30 =√3/3

2、sin45 =cos45 =√2/2，tan45 = 1

3、sin60 =√3/2，cos60 = 1/2，tan60 =√3

The common inference methods of trigonometric function value of acute angle are: sin (-α) =-sin α, cos (-α) = cos α, tan (-α) =-tan α, cot (-α) =-cot α, sin (π/2-α) = cos α, cos (π/2-α).

Expand the data acute angle trigonometric function value, when the angle changes between 0 and 90, the trigonometric function value changes:

1, the sine value increases (or decreases) with the increase (or decrease) of angle, and the cosine value decreases (or increases) with the increase (or decrease) of angle;

2. Tangent value increases (or decreases) with the increase (or decrease) of angle, and cotangent value decreases (or increases) with the increase (or decrease) of angle;

3. Secant value increases (or decreases) with the increase (or decrease) of angle, and cotangent value decreases (or increases) with the increase (or decrease) of angle.

References:

Baidu encyclopedia-acute triangle function