Mathematics in the senior high school entrance examination will examine many contents, the most basic of which is mathematical formula. I sorted out some important mathematical formulas.

Perimeter formula The following types are common in junior high school mathematics perimeter formula:

Rectangular perimeter = (length+width) ×2, C=2(a+b)

Square perimeter = side length ×4, C=4a

Circumference = diameter × π, C=2πr

Area Formula The common geometric area formulas in junior high school mathematics have the following types:

Rectangular area = length × width, S=ab

Square area = side length × side length, S=a?

Formulas of trigonometric functions 1, two-angle sum formula

sin(A+B)=sinAcosB+cosAsinB

sin(A-B)=sinAcosB-sinBcosA

cos(A+B)=cosAcosB-sinAsinB

cos(A-B)=cosAcosB+sinAsinB

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

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

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

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

2. Double angle formula

tan2A=2tanA/( 1-tan2A)

ctg2A=(ctg2A- 1)/2ctga

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

3. Half-angle formula

sin(A/2)=√(( 1-cosA)/2)

sin(A/2)=-√(( 1-cosA)/2)

cos(A/2)=√(( 1+cosA)/2)

cos(A/2)=-√(( 1+cosA)/2)

tan(A/2)=√(( 1-cosA)/(( 1+cosA))

tan(A/2)=-√(( 1-cosA)/(( 1+cosA))

ctg(A/2)=√(( 1+cosA)/(( 1-cosA))

ctg(A/2)=-√(( 1+cosA)/(( 1-cosA))

4. Sum-difference product

2sinAcosB=sin(A+B)+sin(A-B)

2cosAsinB=sin(A+B)-sin(A-B)

2cosAcosB=cos(A+B)-sin(A-B)

-2sinAsinB=cos(A+B)-cos(A-B)

sinA+sinB = 2 sin((A+B)/2)cos((A-B)/2

cosA+cosB = 2cos((A+B)/2)sin((A-B)/2)

tanA+tanB=sin(A+B)/cosAcosB

tanA-tanB=sin(A-B)/cosAcosB

ctgA+ctgBsin(A+B)/sinAsinB

-ctgA+ctgBsin(A+B)/sinAsinB

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

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

The above is the mathematical formula I compiled, I hope it will help you.