I. formulas of trigonometric functions

1, sum of two angles formula

sin(A+B)= Sina cosb+cosAsinBsin(A-B)= Sina cosb-sinBcosA

cos(A+B)= cosa cosb-Sina sinb cos(A-B)= cosa cosb+Sina sinb

tan(A+B)=(tanA+tanB)/( 1-tanA tanB)tan(A-B)=(tanA-tanB)/( 1+tanA tanB)

2. Double angle formula

tan2A = 2 tana/( 1-tan2A)ctg2A =(ctg2A- 1)/2c TGA

cos2a = cos2a-sin2a = 2 cos2a- 1 = 1-2 sin2a

Second, the area formula:

Side area of right-angle prism S=c*h

Side area of oblique prism s = c' * h

The side area of a regular pyramid is S= 1/2c*h'

The side area of the prism is s = 1/2(c+c')h'

The lateral area of the frustum of a cone is s =1/2 (c+c') l = pi (r+r) l.

The surface area of the ball S=4pi*r2.

The lateral area of the cylinder is s = c * h = 2pi * h

The lateral area of the cone is s =1/2 * c * l = pi * r * l.

Third, the commonly used formula of factorization.

1, square difference formula: a? -B? =(a+b)(a-b)

2. Complete square formula: a? +2ab+b？ =(a+b)？

3. Cubes and formulas: A? +b？ =(a+b)(a？ -ab+b？ )

4. Cubic difference formula: a? -B? =(a-b)(a？ +ab+b？ )

5. Complete cubes and formulas: a? +3a？ b+3ab？ +b？ =(a+b)？

6. Complete cubic difference formula: a? -3a？ b+3ab？ -B? =(a-b)？

7. Three complete square formulas: A? +b？ +c？ +2ab+2bc+2ac=(a+b+c)？

8. Three cubes and formulas: A? +b？ +c？ -3abc=(a+b+c)(a？ +b？ +c？ -ab-bc-ac)

Four, the area formula of common graphics

Area of rectangle = length× width S=ab

Area of a square = side length × side length S=a?

Area of triangle = base × height ÷2S=ah÷2

Area of parallelogram = base × height S=ah

Trapezoidal area = (upper bottom+lower bottom) × height ÷2S=(a+b)h÷2.

Area of circle = π× radius× radius

Five, perimeter formula

Circle: C=πd=2πr (d is diameter, r is radius, π).

The circumference of a triangle is C = a+b+c(abc is three sides of a triangle).

Quadrilateral: C=a+b+c+d(abcd is the side length of quadrilateral)

Rectangle: C=2(a+b) (a is long and b is wide)

Square: C=4a(a is the side length of the square)

Polygon: C= sum of all sides.

Sector circumference: C = 2R+nπR÷ 180? (n= central angle) = 2R+kR (k= radian)