If the complex number Z1 = - 1 and Z2 = 2 + I correspond to the points P and Q on the complex plane respectively, then the complex number corresponding to the vector PQ is______ ．

If the complex number Z1 = - 1 and Z2 = 2 + I correspond to the points P and Q on the complex plane respectively, then the complex number corresponding to the vector PQ is______ ．

∵ complex number Z1 = - 1, Z2 = 2 + I, ∵ z2-z1 = (2 + I) - (- 1) = 3 + I. ∵ complex number corresponding to vector PQ: 3 + I. so the answer is: 3 + I

If a + B = 2, then the square root of ab ≤ 1 (2) if a + B = 3, then the square root of ab ≤ 3
Given positive numbers a and B, we have the following propositions:
(1) If a + B = 2, then the square root of ab ≤ 1
(2) If a + B = 3, then the square root of AB is ≤ 3;
(3) If a + B = 6, then the square root of ab ≤ 3
According to the laws provided by the above three propositions, we can guess that:
If a + B = 9, then the square root of ab ≤ ()
If a + B = n (n is greater than or equal to zero), then the square root of ab ≤ ()

If a + B = 9, then the square root of ab ≤ 9 / 2
If a + B = n (n is greater than or equal to zero), then the square root of ab ≤ n / 2
This is derived from a theorem

The distance between a and B is 980km. The two trains leave each other from two stations. The express train runs 60 kilometers per hour. After 10 hours, the two trains meet and the local train runs every hour
How many kilometers?

Set the local train to run x kilometers per hour
After 10 hours, 60 * 10 km for fast train = 600 km, 10 x km for slow train
Because it's a meeting, 600 km + 10x km = 980
We get x = 38

The average of the three numbers is 14. Two of them are 11 and 9. What's the other number
If you answer well, give it points. Hurry up! It's urgent!

14×3=42
42-11-9=22
The other number is 22

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 = (46 + 4) × 2, the number 100 is in the fourth column of row 46 Column 25, column 2, column 20, column 3, column 46, column 4

A number is composed of 8 10, 4 0.1 and 2 0.001, which is ()

This number
=8×10+4×0.1+2×0.001
=80.402

On a map with a scale of 1:2000000, the distance between a and B is 8 cm. How many km is the actual distance between a and B?
If the distance between a and B is 10 cm measured on another map, what is the scale of the other map?

160km
1：2500000

There is a quadrilateral ABCD (as shown in the figure),

Because the angle B = 90 degrees, ab = 4, BC = 3, so AC = 5 (Pythagorean theorem), and because ad = 13, CD = 12,5 ^ 2 + 12 ^ 2 = 13 ^ 2, so CD ^ 2 + AC ^ 2 = ad ^ 2, according to the inverse theorem of Pythagorean theorem, the angle DCA = 90 degrees, so the quadrilateral area = 1 / 2 * 3 * 4 + 1 / 2 * 12 * 5 = 36

There are 360 tons of coal in two piles. Two thirds of coal in pile a is equal to three fourths of coal in pile B. how many tons of coal are there in pile a and pile B?
10 minutes! Urgent! Please

Lie equation
Let a weigh x, B weigh y
Then x + y = 360
X*2/3=Y*3/4
The solution is x = 190, y = 170

If the solution set of inequality x2 + (A-1) x + 1 ＜ 0 about X is φ, then the value range of real number a is______ ．

The solution set of inequality x2 + (A-1) x + 1 ＜ 0 about X is ∈ △ = (A-1) 2-4 ≤ 0, and the solution is - 1 ≤ a ≤ 3, so the value range of real number a is [- 1, 3], so the answer is [- 1, 3]