First, the mathematical two-angle sum formula

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

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

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

4、ctg(A+B)=(ctgActgB- 1)/(ctg B+ctgA)ctg(A-B)=(ctgActgB+ 1)/(ctg B-ctgA)

Second, the mathematical ellipse formula

1, ellipse circumference formula: 1=2πb+4(a-b).

2. ellipse circumference's Theorem: The circumference of an ellipse is equal to the short axis of an ellipse, and the circumference of a circle with a radius of (2πb) plus four times the difference between the long axis (a) and the short axis (b) of an ellipse.

3. Elliptic area formula: s=πab.

4. Ellipse area theorem: the area of an ellipse is equal to π times the product of the major semi-axis length (a) and the minor semi-axis length (b) of the ellipse.

Three, the double angle formula

1、tan2a = 2 tana/( 1-tan2a)ctg2a =(ctg2a- 1)/2c TGA

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