In Rt△, sinA= the opposite side/hypotenuse of angle A; CosA= adjacent side/hypotenuse of angle a; TanA= opposite side of angle a/adjacent side of angle a.

2. The relationship between complementary trigonometric functions.

Sina = cos (90-a); cosA=sin(90-A)

tanA= 1/tan(90-A)

3. The relationship between trigonometric functions with the same angle

Sina Plaza +cosA Plaza = 1

tanA=sinA/cosA

4. Trigonometric function values of three special angles

sin30= 1/2

Sin45= root number 2/2

Sin60= root number 3/2

Cos30= root 3/2

Cos45= root 2/2

cos60= 1/2

Tan30= root number 3/3

tan45= 1

Tan60= root 3

5. Solve the right triangle

Solution of right triangle with known two sides

A right triangle with one side and one angle is known.

6. Solve the application of right triangle.

(1) Finding Right Triangle in Practical Problems

(2) Several common graphics

(3) Slope and toe problems

Slope I = 1: m (indicating the ratio of vertical rising height to horizontal advancing distance)

The slope angle refers to the included angle between the slope surface and the horizontal ground (tangent to the toe of the slope = slope).