I just got the wrong number!

I just got the wrong number!

2740mm = 2.74M 1525mm = 1.525m 25mm = 0.025m 2.74 × 1.525 + 0.025 × 2.74 × 2 + 0.025 × 1.525 × 2 = 4.39175 (M2)
Such a simple question,

If the relationship between ∠ 1 and ∠ 2 is an internal stagger angle, how many degrees does ∠ 1 equal to 40 degrees and ∠ 2 equal to? Why?

The relationship between ∠ 1 and ∠ 2 is internal stagger angle, and ∠ 1 is equal to 40 degrees, but the degree of ∠ 2 cannot be determined
Because the internal angle is equal, two lines must be parallel
May I help you!

Is the square Q of negative p a monomial

-P & #178; q is a monomial

In the expansion of (x2 + 1 / x2-2) 3, the constant term is
A.-4 B.-8 C.-12 D -20

Turn x ^ 2 + 1 / x ^ 2-2 into (x - 1 / x) ^ 2
Then the original formula = (x - 1 / x) ^ 6
The expansion is constant only if the degree of X is equal to that of 1 / X
So the constant term is C (6,3) * - 1) ^ 3 = - 20

In the rectangular coordinate system, the coordinates of vertex A and B of triangle ABC are (- 1, - 2), (3, - 2) respectively, and vertex C moves on the straight line y = x + 2
1. When the area of triangle ABC is 6, try to find the coordinates of point C and draw the triangle ABC
2. When the triangle ABC is a triangle with ab as the base, the coordinate of point C is calculated

1. Which line does vertex C move on? The line told should be able to determine the abscissa of point C, and its ordinate should be 1 or - 5. Find out the length of line AB as 4, use the triangle area formula to find out the height as 3, set the ordinate of point C as x, then the absolute value of X + 2 is equal to 3, and then find out x, that is, the ordinate of point C
2. In isosceles triangle, point C moves on the straight line x = 1 (y is not equal to - 2). If the area is still 6, then C (1,1) or (1, - 5). If the area is not 6, then the ordinate of C can be obtained according to the method of the first question above

The third power of X - the second power of X - x + 1
Factorization

x³-x²-x+1
= x²(x-1)-(x-1)
= (x-1)(x²-1)
= (x-1)(x+1)(x-1)
= (x-1)²(x+1)
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If a is an integer, where is the origin of the point representing the number a on the number axis?

It's 0

Find the minimum value of 4x ^ 2 + y ^ 2-2y-4y + 15

The answer is 6
4x^2+y^2-2y-4y+15 = 4x^2+y^2-6y+15 = 4x^2+(y - 3)^2 + 6.
The minimum value of 4x ^ 2 is 0. The minimum value of (Y - 3) ^ 2 is 0. So the answer is 6

The resistance of a motor coil is 20 Ω, connected to a 220 V power supply, and the power of the motor is 4.4 kW
1: Calculate the electric energy consumed by the motor for one hour
2: Heat generated on the coil of the motor when it works for one hour
3: What is the efficiency of the motor without considering other energy losses?

First of all, a data in your question: "the coil resistance of the motor is 20 Ω" must be wrong. It is impossible to have such a large resistance. If there is such a large resistance, the following "power is 4.4kw" will not be realized
It is estimated that the resistance of the motor is 2 Ω
The circuit is a junior high school physics problem. That is DC
1. The formula w = P * t is used unconditionally and can be used in motors
So we can get: w = 4.4kw * 1H = 4.4kwh (that is 4.4 degrees)
2. According to the formula P = u * I (this formula is also used unconditionally and can be used on motors)
I=P/U=4.4kW/220V=20A
The formula for calculating heat is as follows:
Q = I ^ 2 * r * t = 20A * 20A * 2 Ω * 3600 seconds = 2880000 joules
3. From the first question, this motor consumes 4.4kwh of electric energy when it works for 1 hour = 4.4 * 1000W * 3600s = 15840000 joules;
Of these, 2.88 million coke turns into heat, and the rest into mechanical energy
The converted mechanical energy is: 15840000-2880000 = 12960000 (this is useful work)
Mechanical efficiency η = 12960000 coke / 15840000 coke = 0.818 = 81.8%
finish

If x 2-x + 1 / x = 1 / 6, what is the value of the fourth power of x-3x2 + 1 / x2?

As a result of x-x + 1, it is one of the times of x-x + 1, and it is one of the 6-one-of-x-x-1, and it is one of the six-one-of-x-1 = 6xx \\\\\\\\\\\\\\\\\\\\\\\\35\\\\\\\\\\\\\\\\\\\\\ifyou don't understand, you can ask