Find the curve integral I = ∫ Γ z2ds, where Γ is the curve x2 + Y2 + Z2 = 4, x + y + Z = 0

Find the curve integral I = ∫ Γ z2ds, where Γ is the curve x2 + Y2 + Z2 = 4, x + y + Z = 0

Find the tangent and normal plane equation of curve x2 + 3y2 + Z2 = 9, Z2 = 3x2 + Y2 at point (1,1,2)

Eliminate y to get x ^ 2 + 3 (3x ^ 2-z ^ 2) + Z ^ 2 = 9, derive x to get 20x - 4Z * Z '(x) = 0, so Z' (x) = 5x / z = 5 / 2, eliminate x to get Z ^ 2 = 3 (9-z ^ 2-3y ^ 2) + y ^ 2 = > 4Z ^ 2 + 8y ^ 2 = 27, derive y to get Z '(y) = - 2Y / z = - 1, so the tangent vector is (5, - 2,2) and the tangent is (x-1) / 5 = (1-y) / 2 = (Z -

What is the relationship between current, voltage, power and resistance?

Voltage U = IR current times resistance
Power equals current times voltage P = UI = I * I * r = u * U / R

In 1 / x, 1 / 2, x ^ 2 + 1 / 2, 3 / x + y, a + (1 / M), the number of fractions is

The fractions are: 1 / x, 3 / (x + y): a + (1 / M)

How much is the actual power when a 220V 100W incandescent lamp is connected to a 240V circuit?

R=U^2/P
So r = 220 ^ 2 / 100 = 484 Ω
P = U^2/R = 240^2/484 = 119W

A / A-B 3B / 2a-2b

2a/2(a-b)
3b/2a-2b

The electric appliance is about 2000 W, the voltage is 220 V, the distance between the main line is 100 m, using two lines of open wire covered with plastic pipe, can 2.5 square copper wire bear the load?

One kilowatt of 220 V household appliances has a current of about 4.5 amperes, and the 2.5 square copper wire can withstand about 20 amperes, which means that in principle, it can carry two such loads, but it is better not to use them for a long time

A cuboid room is 5.2 meters long, 3 meters wide and 6 meters long. The lower part of its four walls is painted with 1.1 meters high light green paint (1 square meter of the door opening is not painted). How many square meters are the painted area? The upper part of the four walls and the roof are painted with white paint (10 square meters of doors and windows are not painted), and how many square meters are the painted area?

Total area 5.2 * 3 + (5.2 + 3) * 2 * 2.6 = 15.6 + 42.64 = 58.24
Green area = (5.2 + 3) * 2 * 1.1-1 = 18.04-1 = 17.04
White area = 58.24-17.04-10 = 31.2

Given that the power consumption of refrigerator is 0.45 degrees per day, the power consumption of refrigerator is 18.75w. Is that right
Given that the power consumption of refrigerator is 0.45 degrees per day, the power consumption of refrigerator is 18.75w. Is that right

In normal use, the average power of this refrigerator is 18.75w; in fact, the compressor power of household refrigerator is about 100-160w,
The compressor starts up for a period of time and stops for a period of time. When it starts up, the power is more than 100 watts, when it stops, the power is zero watts, so the average power consumption is about 18.75 watts. The actual power consumption of the refrigerator is related to the use environment, the number of door opening, the number of food and other factors, and is not fixed

A ∧ B = A & # 178; - 2b, if 1 ∧ 2 = - 3, what is x ∧ 2

According to the definition of asterisk, a is equivalent to x, B is equivalent to (X-2)
Then x * (X-2) = x ^ 2-2 (X-2) = x ^ 2-2x + 4
I hope you can understand it. I hope it will help you