Math formula of senior one to senior three: 1, square difference formula: a? -B? =(a+b)(a-b).
2. Complete square formula: a? +2ab+b？ =(a+b)？ .
3. Cubic sum formula: A? +b？ =(a+b)(a？ -ab+b？ )。
4. Cubic difference formula: a? -B? =(a-b)(a？ +ab+b？ )。
5. Complete cubic sum formula: 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. the formula of cubic sum of three terms: a? +b？ +c？ -3abc=(a+b+c)(a？ +b？ +c？ -ab-bc-ac).
Lateral area: S=c*h, the key mathematical formula for grades one to three.
Side area of oblique prism: S = c'* h
Side area of a regular pyramid: S= 1/2c*h'
Side area of prism: S = 1/2(c+c')h'
Area of frustum side: s =1/2 (c+c') l = pi (r+r) l.
Surface area of the ball: S=4pi*r2.
Area of cylinder side: s = c * h = 2pi * h
The lateral area of the cone: s =1/2 * c * l = pi * r * l.
Arc length formula: l=a*r.a is the radian number r >； of the central angle; 0
Sector area formula: s =1/2 * l * r.
Cone volume formula: V= 1/3*S*H
Cone volume formula: V= 1/3*pi*r2h.
Oblique prism volume: V=S'L Note: where s' is the straight cross-sectional area and l is the side length.
Cylinder volume formula: v = s * h；; Cylinder V=pi*r2h
Acute angle formula of formulas of trigonometric functions trigonometric function in junior middle school
Opposite side/hypotenuse of sinα=∞α
Adjacent edge/hypotenuse of cosα=∞α
Opposite side of tanα = adjacent side of ∠ α/∠α.
Adjacent side of cotα = opposite side of ∠ α/∠α.
Double angle formula
Sin2A=2SinA？ Kosa
cos2a=cosa^2-sina^2= 1-2sina^2=2cosa^2- 1
tan2A=(2tanA)/( 1-tanA^2)
(Note: Sina 2 is the square of Sina 2 (a))