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How to read English words
shoes[∫u:z]
It is known that in the arithmetic sequence {an}, tolerance = 6, and an = 22, the first n terms and Sn = 28, find A1 and n
An = a1 + (n-1) d = a1 + 6n-6 = 22sn = n (a1 + an) / 2 = n (a1 + 22) / 2 = 28, so a1 + 6N = 28na1 + 22n = 56, so A1 = 28-6n, so 28n-6n & sup2; + 22n = 56, that is 3N & sup2; - 25N + 28 = 0, then (3n-4) (N-7) = 0, then n = 4 / 3 (not integer, rounding off) or n = 7, so n = 7 brings n = 7 into a1 + 6N =
Let C be the straight line segment from point a (1,1) to point B (2,3), and calculate the curvilinear integral of coordinates ∫ C (X-Y) DX + (x + y) dy
(3 / 4 minus 1 / 6) × 12 simple calculation
(3 / 4 minus 1 / 6) × 12
=3 / 4 × 12 minus 1 / 6 × 12
=9-2
=7
If the volume formula of the frustum is v = 1 / 3 Π H (R ^ 2 + R + R ^ 2) or V = 1 / 3 Π H (R ^ 2 + 2R + R ^ 2), the quick solution can be obtained
The volume formula of the frustum: (R1 * R1 + R2 * R2 + R1 * R2) * 3.14 * H / 3 R1, R2 and H are the radii of the top and bottom of the frustum and the height of the frustum respectively
What is the condition for the existence of partial derivative of binary function at a point to be differentiable
The existence of the partial derivative of a function of two variables at a point is neither sufficient nor necessary
Is ice and water the same substance
Chemical change of water formed by ice
Yes
No. physical change
There are already some people waiting in line at the gate of a park before the check-in starts. After the check-in starts, there are 10 people queuing up for check-in every minute, and one gate can let 25 people in every minute. If there is only one gate, there will be no one queuing 8 minutes after the check-in starts; if two gates are opened at the same time, how many minutes after the check-in starts?
According to the analysis, 25 × 8-10 × 8, = 200-80, = 120 (people); 120 ^ (25 × 2-10), = 120 ^ 40, = 3 (minutes); a: if two check-in gates are opened at the same time, no one will queue up three minutes after the check-in begins
If log2 (m)
First, Log1 / 2 (n) is transformed into - log2 (n) and then log2 (1 / N),
Then consider 1 as log2 (2)
So the formula becomes
log2（m）
One sixth more than 36 is ()
Why not 36 and one sixth? （36+1/6）
36 × (1 + 1 / 6) = 36 × (7 / 6) = 42
One sixth more than 36 is 42
It's customary to regard 1 / 6 here as a proportion rather than a specific value
RELATED INFORMATIONS
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- 6. Is 2100 a leap year? We have tried, from 2008 to 2100, why is the year that can be divided by 100 but not by 400 not a leap year? 2100 is not a leap year, 2099, 2098, 2101 and 2102 are not leap years. Isn't this unreasonable? (is this scientific truth)
- 7. What is the KM unit on the highway? For example, how many kilometers is 1km
- 8. The length of a line is 450m, and the speed is 90m per minute. In order to convey an order, the correspondent rushes from the end of the line to the head of the line, and then rushes back to the end of the line immediately. His speed is 3M per second. Question: (1) how long does it take for the correspondent to go from the end of the line to the end of the line? (2) What is the distance and displacement of the correspondent?
- 9. Add "+" or "-" in front of the numbers 3, 4, 5, 6, 7, 8 and 9 to make their sum - 10. Write as many as possible and list the formula It's three, four, five, six, seven, eight, nine
- 10. Given the function f (x) = 1 + ln (x + 1) / x, the domain of function definition is obtained
- 11. Why is the superposition principle only applicable to linear circuits
- 12. Page 25 of physics, when the car is not at the highest point of the arch bridge or the lowest point of the concave bridge, can we use the appeal method to solve it If the car is not at the highest point of the arch bridge or the lowest point of the concave bridge, it can be solved by the appeal method On page 25 of the physics book, is the centripetal force on the middle and both sides of the bridge the same when the car crosses the bridge? When the speed is at the highest point, it can't exceed a certain limit. That is, the speed is different, and the center of gravity on both sides of the bridge is different. So is the centripetal force the same?
- 13. 45% of a number is equal to 3 / 8 of 32. What's the number? (solve the equation)
- 14. The weight ratio of goods in warehouse A and warehouse B is 7:8, If 6 tons are transported into warehouse A, warehouse a will have 14 tons more than warehouse B, The original goods in warehouse A are () tons emergency Formula explain
- 15. 80% of the boys in Grade 6 are equal to two-thirds of the girls. The ratio of boys to girls is (:)
- 16. The motorcycle wheels rotate rapidly and look like a whole plane, which shows that______ ．
- 17. The speed of the train is 75% of the speed of the bus. The two trains leave from a and B at the same time and meet at a distance of 6 km from the midpoint
- 18. 1, if two cars start from two places at the same time and travel along the same road, 2 hours Cars travel 100 kilometers per hour, buses 80 kilometers per hour 1. If two vehicles start from two places at the same time and travel along the same road, they will meet at the gas station two hours later. How long is the road between the two places? 2. If two vehicles start from the gas station at the same time and travel along the same road opposite each other, they will arrive at the destination at the same time in two hours. How long is the road between the two places?
- 19. The students of four classes in grade seven of a school plant trees voluntarily on the tree planting day. Class one plants x trees, class two plants 40 trees less than twice of class one, class three plants 30 trees more than half of class two, and class four plants 30 trees more than half of class three. (1) how many trees do the four classes plant? When x = 60, which of the four classes has the most trees?
- 20. How many hours does it take for the bus and truck to complete the whole journey?