I1 and I2 represent the change of current. How to understand I1 = - I2

I1 and I2 represent the change of current. How to understand I1 = - I2

-It indicates that the current direction is the opposite direction, which is often used in the calculation of DC circuit

If the effective value of I1 + I2 is 10.4a, the phase difference between I1 and I2 may be a.0 b.30 ° C60 ° D90 °

If two resistors are connected in parallel, R1: R2 = 3:4, and the current I1 is 4A larger than I2, what should I1 be?

The voltage on the parallel resistance is equal, the voltage is equal to the current times the resistance: i1r1 = i2r2
In addition, I2 = I1 + 4 is brought into the above formula to solve I2 = 12a

It takes 10 hours for car a to complete the whole journey alone and several hours for car B to complete the whole journey
Car a and car B start from two places at the same time, and they meet after 6 hours. It takes 10 hours for car a to complete the whole journey alone, and how many hours for car B to complete the whole journey?

1 ÷ (1 / 6-1 / 10) = 15 (hours)

If 4A + 6B, then a; b=

4a=6b
a:b=3:2

How to change a tire
There is a transport driver who is going to start. He uses a tricycle with a tire life of 20000 Li. Now he has to run for 50000 Li and plans to use eight tires to complete the task. How can he do that?

Number the tires 1,1,1,2,2,3,4,4
First run 2 kilometers with 1.1.1, then run 1 kilometer with 2,2,3, then run 1 kilometer with 3,4,4, and then run 1 kilometer with 2,2,4 or 2,4,4
This is only one, at least there should be more than two methods, in fact, no difference

Find the equation of the circle passing through two points a (- 1,4), B (3,2) and the center of the circle on the y-axis

If the circle passes through AB, the center of the circle is on the AB vertical bisector (- 1 + 3) / 2 = 1, (4 + 2) / 2 = 3AB, the midpoint is C (1,3) AB, the slope of AB is (2-4) / (3 + 1) = - 1 / 2, so the slope of AB vertical bisector is - 1 / (- 1 / 2) = 2, so the AB vertical bisector is Y-3 = 2 (x-1) and the center is on the Y axis, then x = 0, so Y-3 = - 2, so the center D (0,1) is R & sup2; = | ad

For a batch of goods, car a operates for 8 hours and car B operates for 12 hours. After two cars are transported at the same time, car a transports 10 tons more than car B. how many tons of this batch of goods?

8x + 10 = 12x x = 2.52.5x12 = 30
So this shipment is 30 tons!
Primary school students can do it! What are you doing with this kind of problem!

If 2A + 7 and 1-A are opposite numbers, then the solution of the equation 4-2a = 3x-1 is?
Urgent notice~

2a+7=-(1-a)
2a+7=-1+a
a=-8
Import a = - 8 into 4-2a = 3x-1
Then: 4-2a = 3x-1
4-2(-8)=3x-1
4+16=3x-1
20=3x-1
x=7

After a part of a pile of yellow sand is used up, the remaining 36 tons is 1 / 5 of the original. If the remaining 60 tons is a fraction of the original?

Method 1: set the original total x tons
1/5*X=36
X=5*36=180
The remaining 60 meals are 60 / 180 = 1 / 3 of the original
Method 2: let the remaining 60 tons be the original X
36/60=1/5X
36X=60*1/5
36X=12
X=12/36=1/3