Arrange some numbers in the following table: the first column, the second column, the third column, the fourth column, the first row 14510, the second row 481012, the third row 9121514? (2) What are the rows and columns of the number 81? (3) What are the rows and columns of the number 100?

(1) The number in the second column of row 10 is 4 × 10 = 40; (2) because 81 can only be the square of 9, the number 81 is in the first column of row 9; (3) ∵ 100 = 102, the number 100 is in the first column of row 10; ∵ 100 = 4 × 25, the number 100 is in the second column of row 25; ∵ 100 = 5 × 20, the number 100 is in the third column of row 20; ∵ 100 = 50 × 2 =

1. If X-Y = 5, x ^ 2-y ^ 2 = 35, then x + y=___
2. If 3 ^ x = 12 and 3 ^ y = 4, then 27 ^ X-Y=_
3. If x ^ 2 + 1 / 2XY + ay ^ 2 is a complete square, then a=
4. Given x + 1 / x = 5, then x ^ 2 + x ^ 2 / 1=____
5. Calculation (process) - 3 ^ 2 * 2009 △ 3 ^ - 2
6. Using integral multiplication formula to calculate (process) 123 ^ 2-122 * 118

1. X ^ 2-y ^ 2 = (x + y) * (X-Y) so (x + y) = 7 2. If 3 ^ x = 12,3 ^ y = 4, then 3 ^ (X-Y) = 3 ^ X / 3 ^ y = 3, so 27 ^ (X-Y) = [3 ^ (X-Y)] ^ 3 = 3 ^ 3 = 27 3

An electric fan with resistance of 20 Ω, working voltage of 220 V, working current of 0.5 A, how much electric energy does it consume for one hour

P=220V*0.5A=110w=0.11kw
W=Pt=0.11kw*1h=0.11kwh
PS: we can't use I ^ 2rt here~

The focus of the ellipse x2 / 12 plus Y2 / 3 equals 1 is F1 and F2! The point P is on the ellipse. If the midpoint of the segment Pf1 is on yzou, then Pf1 is PF2
The focus of the ellipse x2 / 12 plus Y2 / 3 equals 1 is F1 and F2! The point P is on the ellipse. If the midpoint of the segment Pf1 is on yzou, how many times of Pf1 is PF2

F1 (- 3,0), F2 (3,0), F1 (- 3,0), F2 (3,0), F1 (- 3,0), F2 (- 3,0), F2 (- 3,0), F1 (- 3,0), F2 (- 3,0), F2 (- 3,0), F2 (- 3,0), F2 (-,
The midpoint of the segment Pf1 is on the y-axis,
So p (3, b), substituting P (3, b) into the ellipse X212 + Y23 = 1, we get B2 = 34
So | P F1 | = 36 + 34 = 1472, | P F2 | = 0 + 34 = 32
That is | Pf1 | PF2 | = 147232 = 7

What are the electrical appliances that convert electric energy into chemical energy

Rechargeable battery, when charging, converts electrical energy into chemical energy

1、you disagree with him,_____ you?
A、don't B、do C、can D、can't
What do you choose for this question? Write down the reasons. I think you can choose B, but the answer is a,

The negative meaning of disagree has nothing to do with the rhetorical question. The affirmative or affirmative is only related to the form, not to the meaning of the word

What kind of battery can provide 220 V voltage and how much power can be used

Well, a dry battery of 1.5V and a lead-acid battery of 2V,
Series connection, that's OK. But what do you do when you make DC 22V?
As for the power, it depends on the internal resistance of the battery. The total internal resistance is the sum of all!

It is known that the sum of the first n terms of the sequence an is Sn, and 1 / S &; + 1 / S &; +... + 1 / Sn = n / N + 1 (n belongs to n )
1: Find S &;, S &;, Sn
2: Let BN (n is the number of items) = (1 / 2) & # 710; an (n is the number of items), and the sum of the first n items of BN is TN (n is the number of items). If TN (n is the number of items) belongs to (1 / m, M & # 178; - 6m + 16 / 3) for all n , find the value range of real number m!

1. When n = 1, 1 / S1 = 1 / (1 + 1) = 1 / 2, S1 = 2n = 2, 1 / S1 + 1 / S2 = 1 / 2 + 1 / S2 = 2 / 31 / S2 = 2 / 3-1 / 2 = 1 / 6, S2 = 6N = 1, S1 = 2n ≥ 2, 1 / S1 + 1 / S2 +... + 1 / Sn = n / (n + 1) (1) 1 / S1 + 1 / S2 +... + 1 / S (n-1) = (n-1) / N (2) (1) - (2) 1 / Sn = n / (n + 1) - (n-1) / N = [n & # - (n +...)

If the volume of a cylinder is (π R & # 179; + π R & # 178; H) and the height is (R + H), then the bottom area of the cylinder is

Floor area
=Volume × height
=（πr³+πr²h）÷（r+h）
=πr²×（r+h）÷（r+h）
=πr²

A new operation "": a b = x / (a + b) + Y / A-B is defined. It is known that 1 * 2 = 8, 2 * 3 = 4, then 3 * 4=____
Can you write the process down

Let a system of linear equations of two variables, y, be substituted by 3,4

Arrange some numbers in the following table: the first column, the second column, the third column, the fourth column, the first row 14510, the second row 481012, the third row 9121514? (2) What are the rows and columns of the number 81? (3) What are the rows and columns of the number 100?