What are the scientific formulas that must be memorized in junior high school

Junior high school mathematics must memorize trigonometric function spine clear formulas and trigonometric function values" mainly includes the definition and relation of sine, cosine, and tangent functions.

1) The sine value of a = the opposite side of a: hypotenuse, denoted as sina = a c.

2) The cosine value of a = the adjacent edge of a: hypotenuse, denoted as cosa = b c. Beside it.

3) The tangent of a = the opposite side of a: The adjacent edge of a, denoted as tana=a b.

The math formula that must be memorized in junior high school is as follows:1. The perimeter of the diffuse and rectangular = (length + width) 2 = 2 (a + b) = (a + b) 2 2. The perimeter of the square punch ridge = side length 4 = 4a

3. The circumference of the circle = pi Diameter = d = pi radius 2 = 2 r 4. The area of the rectangle = length and width s = ab

5. The area of the square = the length of the side The length of the side = a

6. The area of the triangle = base height 2s = ah 2

7. The area of the parallelogram = the base height s = ah

8. The area of the trapezoid = (upper bottom + lower bottom) height 2s = (a + b) h 2 9. diameter = radius 2d = 2r

10. Radius = diameter 2r=d 2

Ten. 1. The area of the circle = pi radius radius.

Ten. 2. The area of the triangle = the height of the base 2s = a h 2 ten. 3. The area of the square = the length of the side The length of the side = a a ten. Fourth, the area of the rectangle = length and width s = a b

Ten. 5. The area of the parallelogram = the base height s = a h ten. 6. The area of the trapezoid = (upper bottom + lower bottom) height 2s = (a + b) h 2 ten. 7. Sum of internal angles: The sum of the internal angles of the triangle = 180 degrees.

Ten. 8. The volume of the cuboid = length, width, height, v=abc ten. 9. The volume of the cuboid (or cube) = the base area of the height v = sh two. 10. The volume of the cube = edge length edge length edge length v=aaa

Current intensity: i=q power t

Resistance: Juchang Liang r= l s

Ohm's law: i = u r

Joule's law: q=uit=pt

5.Series circuits:

1)i=i1=i2

2)u=u1+u2

3)r=r1+r2

4)u1/u2=r1/r2

5)p1/p2=r1/r2

6.Parallel fast judgment circuit: Tongyun.

1)i=i1+i2

2)u=u1=u2

7.Fixed-value resistance:

1)i1/i2=u1/u2

2)p1/p2=i12/i22

3)p1/p2=u12/u22

8.Electric work: w=uit=pt=uq

1. Current intensity: i=q power t2. Resistance: r= l s

3. Ohm's law: i=u r

4. Pressure: p=f s

5. Liquid pressure: p= gh

6. Thermodynamic wide temperature: t=t+273k

7. Constant resistance: (1) i1 i2=u1 u2 (2) p1 p2=i12 i22 (3) p1 p2=u12 u22

8. Electric work: (1) w=uit=pt=uq (universal formula) (2) w=i, 2rt=u, 2t r (pure resistance formula).

9. Electric power: (1) p=w t=ui (universal formula) (2) p=i?2r=u?2 R (pure resistance formula).

Actual pulley: f=(g+g) n (vertical direction) 11, work: w=fs=gh (lift the object high).

12. Power: p=w t=fv

13. The principle of work: W bracelet judgment W machine.

14. Actual machinery: w total w has w extra.

15. Mechanical efficiency: w has w total.