Parallel I always = I1 + I2 + I3... Mo u total R total In series Other I total u always add ink directly

parallel connection
U total = U1 = U2 = Un
1 / R total = 1 / (R1) + 1 / (R2) + 1 / (R3) + +1/（Rn）
series connection
I total = I1 = I2 = I3 = in
U total = U1 + U2 + U3 + +Un
R total = R1 + R2 + R3 + +Rn

Who can solve this equation to find I1, I2, I3
i1+i3=i2;
-Us1+R3i3-R1i1=0;
(R2+R4)i2-Us2-R3i3=0;

This is a set of simultaneous equations of branch current normal equations based on Kirchhoff's law. Let me answer it. Sort it out: i1-i2 + I3 = 0 (1) - r1i1 + r3i3 = US1 (2) (R2 + R4) i2-r3i3 = US2 (3) by using elimination method (2) + (3): (R2 + R4) i2-r1i1 = US1 + US2 (4) (2) - R3 * (1) is: - r1i1-r

The two vehicles set out from both places at the same time and travel in opposite directions. Large trucks travel 50 kilometers per hour, and small cars travel 10 kilometers more per hour than large trucks,
Four hours later, the two vehicles are still 40 kilometers apart. How many meters are there between the two places?

(50 + 10 + 50) X4 + 40 = 480km

If an isosceles triangle is known to have two times, 4cm and 8cm respectively, the perimeter is cm. If an angle of an isosceles triangle is 42 degrees, the degree of its base angle is

If an isosceles triangle is known to have two times, 4cm and 8cm respectively, its perimeter is 20cm. If an angle of an isosceles triangle is 42 degrees, its base angle degree is 69 degrees
Perimeter: 8 + 8 + 4 = 20cm
Base angle: (180-42) △ 2 = 69 degrees

A bus from a city to B city, 8 hours to arrive, a truck from B city to a city, 10 hours to arrive, two cars at the same time from the two cities to each other, six hours later, they are 112 kilometers apart. How long is the highway between a and B cities?

1 / 8 of the total travel time per hour for passenger cars and 1 / 10 of the total travel time per hour for freight cars,
The total driving distance of 6-hour buses and trucks is 112 kilometers more than the total length (you can draw a picture by yourself)
By question:
Total length: 112 ÷ [(1 / 8 + 1 / 10) * 6-1] = 320 km
The highway between the two cities is 320 kilometers long

Definition: A is a rational number which is not 1. We call 1 / 1 - a the difference reciprocal of A
For example: the reciprocal of 2 is 1 / 1-2 = - 1, and the reciprocal of - 1 is 1 / 1 + 1 = 1 / 2. It is known that A1 = 1 / 3, A2 is the reciprocal of A1, A2 = (); A3 is the reciprocal of A2, A3 = (); A4 is the reciprocal of A3, A4 = () And so on, then a2011 = ()

It is known that A1 = 1 / 3,
A2 is the inverse of A1
a2=1/(1-1/3)=3/2
A3 is the inverse of A2
a3=1/(1-3/2)=-2
A4 is the inverse of A3,
a4=1/(1+2)=1/3=a1
1 cycle every 3 rounds
The cycle is three
2011÷3=670.1
So a2011 = A1 = 1 / 3

A small wooden block of mass m is suspended on the ceiling with a thin line of length L (which can not be extended). At present, a bullet of mass m hits the wooden block with a horizontal velocity V0 (which does not go through), and the maximum swing angle of the thin line is calculated
The maximum swing angle//

In the process of bullet shooting wood block, the internal force is far greater than the external force, and the momentum conservation of the system is MV = (M + m) v1
v1=mv/(m+M)
Next, the bullet and the block move in a circle, f = (M + m) V ＾ 2 / L
The f direction = (MV) ＾ 2 / (M + m) L
So the tension f = f direction + G = (MV) ＾ 2 / (M + m) l + (M + m) g

Four times of a number plus six times of this number minus three times of this number equals two times of 63. Find this number

63*2÷(4+6-3)=126÷7=18

Force analysis of physical vehicle
A car with wheels. People ride on it. Please analyze the force of people, wheels and the whole
Excuse me? It's the force on the way forward

For wheels:
Vertical direction: downward gravity, downward pressure from axle, upward support from ground
Horizontal direction: the forward pull of the chain and the static friction of the opposite side
Overall:
Gravity, supporting force, static friction force, pulling force
Analysis finished!

It is known that (M2-1) X2 - (m-1) x + 8 = 0 is a linear equation of one variable about X, and the square of M + 4 of X is obtained

∵ (M & # 178; - 1) x & # 178; - (M + 1) x + 8 = 0 is a univariate linear equation ∵ M & # 178; - 1 = 0, M + 1 ≠ 0 from M & # 178; - 1 = 0 to get (M + 1) (m-1) = 0m = - 1 or M = 1 from M + 1 ≠ 0 to get m ≠ - 1. To sum up, M = 1 substitutes M = 1 into the equation to get - 2x + 8 = 02x = - 8x = - 4 ∵ the original formula = - 4 ^ 5 = - 1024. I'm glad to answer for you, for your dream

Parallel I always = I1 + I2 + I3... Mo u total R total In series Other I total u always add ink directly