Geometry 1, square:
Perimeter = side length ×4 C=4a
Area = side length × side length S=a×a
2. Cube:
Surface area = side length × side length× ×6 S Table =a×a×6
Volume = side length × side length × side length v = a× a× a.
3. Rectangular:
Circumference = (length+width) ×2 C=2(a+b)
Area = length × width S=ab
4. Cuboid:
Surface area (length× width+length× height+width× height )× 2s = 2 (AB+AH+BH)
Volume = length× width× height V=abh
Multiplication and factorization (a+b)(a-b)=a? -B?
(A and B)? =a？ 2ab+b？
(a+b)(a？ -ab+b？ )=a？ +b？
(a-b)(a？ +ab+b？ )=a？ -B?
Answer? +b？ =(a+b)？ -2ab
(a-b)? =(a+b)？ -4ab
Power operation 1. Multiplication of the same base power: a m ×a n =a (m+n).
2. power (a m) n = a (mn), product (ab) n = a nb n
3. Division of the same base power: a m÷÷an n = a (m-n).
4. Zero index: a 0 = 1.
Acute angle formula of formulas of trigonometric functions trigonometric function
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))
When the linear function is proportional, the quotient of x and y is certain. In the inverse proportional function, the product of x and y is definite. In y=kx+b(k, b is constant, k≠0), when x increases by m times, the function value y increases by m times; On the contrary, when x is reduced by m times, the function value y is reduced by m times.
1. Find the k value of the function image: (y 1-y2)/(x 1-x2).
2. Find the midpoint of the line segment parallel to the X axis: |x 1-x2|/2.
3. Find the midpoint of the line segment parallel to the Y axis: |y 1-y2|/2.
4. Find the length of any line segment: √ (x 1-x2) 2+(y 1-y2) 2 (note: the sum of squares of (x1-x2) and (y1-y2) under the root sign).