Find some clever mathematical formulas, such as Skillfully counting line segments Number of points x number of basic line segments △ 2 This kind of,
1/2×3/4×5/6×7/8…… ×99/100=(1×3×5×7×9…… ×97×99)/(2×4×6×8…… ×98×100)=(2n-1)!/(2n)!=1/2n=1/100
1/100
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- 1. 30 points reward, to calculate! If you look at each group of formulas below, what are their rules? 1.1/1×2=1/1-1/2 1/2×3=1/2-1/3 1/3×4=1/3-1/4…… 2.1/1+1/2=1+2/1×2 1/2+1/3=2+3/2×3 1/3+1/4=3+4/3×4…… According to the above rule, can you calculate the following questions? 1.1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90 2.11/30-9/20+7/12-5/6+1/2
- 2. Mathematical calculation 834.2 * (1 + x) (1 + x) (1 + x) (1 + x) (1 + x) * (1 + x) (1 + x) (1 + x) = 7875, find out what x is equal to?
- 3. The X of nine minus the (x + 1) of four times three, plus 27 equals 0. Calculate the value of X To write a process, it's about exponents and exponentials
- 4. How to calculate excel circularly For example: a + B + C + D + e = f, and E = f * 0.1, how to calculate this e in Excel and how to set it?
- 5. How to improve the ability of mathematical calculation My mathematical thinking is good, but I calculate the wrong number in my mind all day. What special practice is better. Analytic geometry or something else?
- 6. How to improve the ability of mathematical calculation There are serious problems in calculation. The calculation speed is very slow and easy to make mistakes. There is always a hint in my heart every time I take the exam. I know that the calculation is going to make mistakes. When I get a question, I will be confused even if I see a very simple exponential operation. It's easy to make mistakes in solving equations, and the plus and minus signs are often written wrong, Decimal division takes half a day. Am I useless? Alas, I'm not afraid of doing problems. I just think I'm too stupid. Sometimes I really think I'm not the material of mathematics. Alas, I'm really helpless and desperate. So I'd like to ask you for some specific methods, such as some accurate calculation skills. Thank you very much! There are physical and chemical quite a headache ah, the exam always want to come over!
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- 10. Limx tends to be 1 (the difference between radical X and 1) / (the difference between (3 + x) and (2)
- 11. How to calculate the mathematical formula?
- 12. Mathematical calculation problems, we come in to see When x = (3 radical 3) y = radical 2 Find the value of (X-Y) (x + y) (x ^ 2-xy + y ^ 2) (x ^ 2 + XY + y ^ 2) (sorry, the root number can't be typed)
- 13. 1. If the solution of the equation (a-b) x = the square of A-B is x = a + B, then the relation between a and B is_____ ? 2. Given that the average of a, B and C is 5, and the average of D and E is 6, then the average of a, B, C, D and E is 5_____ ? 3. If 1 / a - 1 / b = 3, then 2A + 3ab-2b / A + 2ab-b=_____ 4. Given that the average of data x1, X2, X3 is a, and the average of data Y1, Y2, Y3 is B, then the average of data X1 + Y1, X2 + Y2, X3 + Y3 is () A.a+b B.1/3(a+b) C.1/2(a+b) D.1/4(a+b) 5. In known trapezoid ABCD, AD / / BC, AE are the vertical lines on the edge of BC, and the perpendicular foot is e. if the trapezoid area is the square of 26cm, the upper bottom ad = 4cm, the lower bottom BC = xcm, and the height AE = YCM, then the relationship between Y and x is () A.y=26/a+x B.y=13/4+x C.y=52/4+x D.(4+x)y=26 6. If the two sides of △ ABC are 5 and 12 respectively, and the other side C is odd, and the sum of the three sides is an integral multiple of 3, then C should be______
- 14. Six practical questions! One choice! Four calculations! Help me! Teach me! 1. A total of 800 kg of oranges and apples are delivered to the store. The weight of oranges and apples is 3:2. How many kg of oranges and apples are delivered to the store? 2. In 2007, my mother deposited 20000 yuan in the bank for two years, with an annual interest rate of 4.68%. According to the regulations at that time, she had to pay 5% interest tax on her income interest. How much after tax interest can my mother get when she matures? 3. To build a 720 meter long highway, one fourth of its total length was built 12 days ago. According to this calculation, how many days will it take to complete the road? 4. When a cake shop sells a cream cake, it always ties a packing belt. The common binding methods are as follows: the bottom circumference of the 7-inch cake box is 62.8 cm, the height is 15 cm, and the joint of the packing belt needs 30 cm. How many meters of packing belt is needed to bind such a cake box? 5. Two fifths of the students in the calligraphy group and 45% of the students in the computer group took part in calligraphy activities, 8 more than those in the calligraphy group, There are 32 people in the chorus. How many more people are in the computer group than in the chorus? Xiao Liang said, "someone must have participated in two of the activities." Xiao Hong said, "not necessarily." who do you think is right? Why? Conclusion: Reason: 6. In the environmental protection activities, class two recycled 810 waste batteries. The ratio of class one and class two was 4:5? Four fifths = 24 △ () = (): 20 There are 80 people on Monday, 100 people on Tuesday, 120 people on Wednesday, 140 people on Thursday and 160 people on Friday. The number of people on the second day increased by ()% compared with the previous day In the following fractions, () cannot be reduced to a finite number. Three fourths, eight eighties, fifty-five, eight twenties 1. 2 / 7 × 11 / 24 + 2 / 7 × 13 / 24 2. 2 / 9 △ [8 / 21 × (1 / 3 + 5 / 12)] 3. 5 / 12 × 5 / 12 + 5 / 12 × 7 / 12 4. 11 / 13 + 11 / 13 × 25
- 15. A: It's said that a 20 yuan membership card can enjoy a 20% discount B: Yes, last time I bought a book, plus the cost of the card, I still have 12 yuan left! What was the original price of the book?
- 16. (1) 1 / 2 * 1 / 3-2 / 3 * 4 / 3
- 17. 1. A cuboid goldfish tank without a cover is 0.6 meters long, 0.3 meters wide, 0.5 meters high and 0.4 meters deep. How many square meters of glass does it take to make the tank? How many liters of water does it take to fill the tank? 2. If a cuboid increases its height by 5 cm, it becomes a cube, and its surface area increases by 180 square cm, How many cubic meters of concrete should be used to cast such a concrete column? If an advertisement is pasted on the surface of the column, what is the maximum utilization area of the advertisement?
- 18. The Spring Festival of 1986 (February 9) is Sunday, and then 1986 What day is it A Monday B Sunday C Friday D Thursday The Spring Festival of 1986 (February 9) is a Sunday. What day is it after the 1986 power day of 1988? () A Monday B Sunday C Friday D Thursday Don't worry about the normal year, leap year? Don't you need to count the mantissa?
- 19. Mathematical calculation requires that the process be clear (1+1×3/1)×(1+2×4/1)×(1+3×5/1)×(1+4×6/1)… X (1 + 97 × 99 / 1) × (1 + 98 × 100 / 1) = how much
- 20. 2008 8 × 2008 9 is equal to? Note: it's 888888 8, not 8 × 8 × 8 9 is the same.