The complex number Z1 = (1 − I1 + I) 2, Z2 = 2 − I3 correspond to the points P and Q on the complex plane respectively, then the complex number corresponding to the vector PQ is () A. 10B. -3-iC. 1+iD. 3+i

The complex number Z1 = (1 − I1 + I) 2, Z2 = 2 − I3 correspond to the points P and Q on the complex plane respectively, then the complex number corresponding to the vector PQ is () A. 10B. -3-iC. 1+iD. 3+i

If Z1 = (1 − I1 + I) 2 = [(1 − I) 2 (1 + I) (1 − I)] 2 = (− 2I2) 2 = − 1. Z2 = 2 − I3 = 2 + I.. P (- 1, 0), q (2, 1), then PQ = (3, 1).. the complex number corresponding to PQ is 3 + I

The complex number Z1 = I / (1-I) ^ 2, Z2 = 2-I ^ 3 correspond to the point P and Q on the complex plane respectively, then the complex number corresponding to the vector PQ is

∵z1=i/（1-i）^2
＝－1／2
z2=2-i^3
＝2＋i
∴P﹙－1／2,0﹚,Q﹙2,1﹚
The vector PQ = (5 / 2,1)
The corresponding complex number is Z = 5 / 2 + I

The distance between the two places is 60 kilometers. After 40 minutes of driving from the two places at the same time, the two vehicles meet. It is known that the speed ratio of the two vehicles is 4:5. How many kilometers do the two vehicles travel per hour

Suppose the speed of car a is 4x km / h, then the speed of car B is 5x km / h. according to the condition of two cars running opposite each other, the equation can be listed as follows: (4x + 5x) * (2 / 3) = 60, where (2 / 3) is the number of hours converted from 40 minutes
You can get x = 10, so you can drive 40 kilometers per hour, and car B can drive 50 kilometers per hour

Solve the following inequality system 4x2-27x + 18 > 0 x2 + 4x + 4 > 0

4X ^ 2-27x + 18 > 0 = = > (4x-3) (X-6) > 0 x > 6 or x0 = = > x ≠ - 2
So the solution of inequality system is (- ∞, - 2) ∪ (- 2,3 / 4) ∪ (6, + ∞)

After several hours, the two cars meet on the way. After the meeting, it takes another eight hours for the truck to arrive at the place A. at this time, the bus has passed the place B and then goes forward for 25% of the distance between the two places. How many hours did it take for the bus and the truck to start and meet

From the departure to the arrival of the freight car in place a, the freight car takes a whole journey between Party A and Party B, and the passenger car takes (1 + 25%) = 5 / 4 of the whole journey
At the same time, the distance ratio is equal to the speed ratio, so the speed ratio of passenger cars and freight cars is (5 / 4): 1 = 5:4
It is also known from the meaning of the title that the 8-hour journey of a freight car equals the journey of a passenger car when it meets
Therefore, it takes 8 △ 5 × 4 = 6.4 hours for the bus
That is, it took 6.4 hours for the bus and truck to meet
The formula is: the speed ratio of passenger to freight is (1 + 25%): 1 = 5:4
Encounter time = 8 △ 5 × 4 = 6.4 hours
Do you understand?

It is known that a, B, C are the three sides of △ ABC, and (A-C): (a + b): (C-B) = - 2:7:1, a + B + C = 24
Find: (1) the value of a, B, C
(2) Judging the shape of △ ABC

(1) Suppose a-c = - 2x, then a + B = 7x, C-B = x, 2A = 6x, then a = 3x, B = 4x, C = 5x, according to a + B + C = 24 = 3x + 4x + 5x = 12x, the solution is x = 2; so a = 6, B = 8, C = 10 (2) because a & sup2; + B & sup2; = 36 + 64 = 100, C & sup2; = 10 * 10 = 100, so a & sup2; + B & sup2; = C & sup2; root

Team a and team B started to build roads at both ends of a road at the same time. After t hour, the two teams completed the task. At this time, team a built 10 kilometers and team B built 8 thousand
Team a repairs () km more per hour than team B

(10-8) / T = 2 / T km
Team a repairs (2 / T) more kilometers per hour than team B

There is a kind of natural number. The sum of its digits is 2003. What is the minimum number in this kind of natural number

The sum of the numbers in each digit is a natural number of 2003. The smallest number is the smallest, and the largest number is 9,
2003÷9=222+5/9,
So the minimum number is 599 Nine of them are 222

There is a bus and a car. The bus runs 85 kilometers per hour. The car runs 120 kilometers per hour. The bus goes three and a half hours first. How many hours does the car take
There is a bus and a car. The bus runs 85 kilometers per hour, and the car 120 kilometers per hour. The bus goes three and a half hours first. How many hours can the car catch up with the bus?

The bus left three and a half hours first
85 × 3.5 = 297.5 (km)
The car caught up with the bus in a few hours
297.5 ÷ (120-85) = 8.5 (hours)

In the triangle ABC, if the angle a equals 90 degrees, a equals 15, C: B = 3:4, then what is b =

4∫5