1,2+3,4+5+6,7+8+9+10…… The general term formula of
The number of the nth line is: 1 / 2n (n-1) + 1,1 / 2n (n-1) + 2 ,1/2n(n+1)
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- 1. 1.5 + 3.6 means () 2.8-0.3 means () 1.2 * 5 means () 20 * 3 / 4 means () 100 / 2 / 5 means ()
- 2. a. B ∈ R, then f (x) = x | SiNx + a | + B is an odd function if and only if () A. a2+b2=0B. ab=0C. ba=0D. a2-b2=0
- 3. Jiugong grid: find the rules and fill in the appropriate numbers 9, 11, 10, 16, (), 12, 17, 8 and 5 in the blank number
- 4. Comparison of static friction and sliding friction
- 5. Divide the three fourths of a meter long rope into six sections, each of which is a fraction of a meter long
- 6. How many hectares is 10000 square meters
- 7. Please help to solve the number reasoning problem: 4 7 9 4 25 ()
- 8. Given that the function FX = 3 ^ x + A / 3 ^ x is even, find the value of A
- 9. 1. Given that the sum of the unknowns X and Y in the system of equations 3x + 5Y = m + 2 is 0, find the index of M and the solution of the system of equations 2x+3y=m 2. When solving the system of equations ax + by = 21, student a misread the sign of B, so the solution is x = 5 cx+y=19 y=-1 Student B missed C and got the solution x = 3. Try to find the solutions of a, B and C y=2, 3. After a shopping mall bought two kinds of clothes, both of them were sold at a price increase of 40%. During the Spring Festival, it was decided to sell the two kinds of clothes at 20% and 10% discount respectively. A customer paid 182 yuan for the two kinds of clothes, and the sum of the two kinds of clothes was 210 yuan. How much was the purchase price and the price of the two kinds of clothes? How many questions can you answer
- 10. What is the calculation formula of commodity profit rate
- 11. There is also a question 1,0,1,8,9, ()?
- 12. 5 / 6 △ 3 / 4-2 / 9 + 3 / 4 The calculation is simple
- 13. If the least common multiple of a and B is 2730, then t=______ .
- 14. The sum of 1 / 4 of a number plus 12 is equal to 2 / 5 of it. Find the number (by solving the equation)
- 15. The blood of the human body accounts for 113% of the body weight. The blood is water. Dad's weight is 78 kg. How many kg does his blood contain?
- 16. () one half is one () one quarter is one () one eighth is one half inside () one quarter quarter () one eighth Be sure to say it today
- 17. A small ball with a mass of 0.1kg is suspended at the top of the inclined plane with an inclination of 37 degrees by a thin wire. The static state of the system is that the rope is parallel to the inclined plane, regardless of all friction, and the system accelerates. When the accelerations are 5 m / s, 10 m / s and 24 m / s, what are the pulling forces on the rope? Specific answer process
- 18. A cup placed on a horizontal table has a mass of 0.2kg and a volume of 5 × 10 ∧ - 4 m #. Now fill the cup with water to find: (1) the mass of water in the cup; (2) the pressure of the cup on the table. (G is 10N / kg)
- 19. Fill the cup with water and put a small wooden block into the cup. The small wooden block floats on the surface of the water. After putting the wooden block, the pressure of the container on the table will not change
- 20. Pour 200g water into the cup, the water depth is 20cm, put 40g wood block, the water surface rises 4cm, ask the pressure of water on the bottom of the cup? The pressure of the bottom of the cup on the table?