What is the meaning of Δ x0 in the formula Δ y = a Δ x0 + O (Δ x0) related to calculus? If the increment of function Δ y = f (x0 + Δ x) & _; f (x0) can be expressed as Δ y = a Δ x0 + O (Δ x0) (where a is a constant independent of Δ x), and O (Δ x0) is infinitesimal higher than Δ x, then the function f (x) is differentiable at point x0, And a Δ x is called the differential of the function corresponding to the increment Δ X of the independent variable at point x0, denoted as Dy, that is, Dy = a Δ X. generally, the increment Δ X of the independent variable x is called the differential of the independent variable, denoted as DX, that is, DX = Δ X. then the differential of the function y = f (x) can be denoted as dy = f '(x) DX. The quotient of the differential of the function and the differential of the independent variable is equal to the derivative of the function. Therefore, the derivative is also called the derivative

Represents the change of the independent variable x at x0

What is the meaning of 0 (Δ x0) in the formula Δ y = a Δ x0 + O (Δ x0) related to calculus?

O (Δ x0) is the higher order infinitesimal of Δ x0, not the equivalent infinitesimal

What is the meaning of x0 in Taylor formula

Taylor formula is a formula that uses the information of a function at a certain point (i.e. x0) to describe the value near it. For example, x0 = 0, Taylor formula means the value of a function near 0

If the two lamps of "220 V 100 W" and "220 V 40 W" are connected in series to the power supply of 440 V, then
A. The lights are on normally
B. A lamp may burn out
C. B lamp may burn out
D. The current does as much work on both lamps

C. B lamp may burn out
According to the partial voltage ratio, if the voltage of B bulb exceeds its rated current greatly, the filament may be burnt out and damaged
Once bulb B is damaged, the circuit is open, and bulb a works without electricity and does not light up

Four rational numbers a.b.c.d. satisfy | ABCD | / ABCD = - 1, find the maximum value of | a | / A + | B | / B + | / C + | / D | / d

Because | ABCD | / ABCD = - 1, ABCD is not all the same sign, and the different sign is odd
It is known that three of the four numbers have the same sign and one is different
It may be three positive and one negative, or three negative and one positive
If it is three positive and one negative, then | a | / A + | B | / B + | C | / C + | / D | / D = 2
If it is three negative and one positive, then | a | / A + | B | / B + | C | / C + | / D | / D = - 2
The maximum is 2

In the circuit shown in the figure, if the slide of sliding rheostat is moved, the indication of voltmeter changes from 6V to 5V, and the indication of ammeter changes by 0.2A, then the change of power consumed by the constant value resistor is ()
A. 0.2WB. 1.0WC. 1.2WD. 2.2W

According to the circuit diagram, the resistance R is connected in series with the sliding rheostat, the voltmeter measures the voltage at both ends of R, and the ammeter measures the current in the circuit; when the indication U1 of the voltmeter is 6V, the current I1 = u1r = 6vr -------- (1) when the indication U2 of the voltmeter is 5V, the current I2 = u2r = 5vr -------- (2) from the title, it can be known that i1-i2 = 0.2A -------- (3) from (1) to (2) it can be obtained that r = 5 Ω, I1 = 6vr = 6v5 Ω = 1 2a, I2 = 5vr = 5v5, Ω = 1a. According to P = UI, the change of power consumed by the constant resistance △ P = P1-P2 = u1i1-u2i2 = 6V × 1.2a-5v × 1A = 2.2W

If we want to make the square of 4A + Ma + 4 a complete square formula, then M=

(4a) ^ 2 + Ma + 4 take a as X, then (4x) ^ 2 + MX + 4 = 16x ^ 2 + MX + 4
To put 16 forward is 16 (x ^ 2 + MX / 16 + 1 / 4)
Now square the formula in brackets to (x + m / 32) ^ 2 = x ^ 2 + MX / 16 + (M / 32) ^ 2
Then we need (M / 32) ^ 2 = 1 / 4 to get m = + 16 or - 16

How many amperes does the general indoor air switch use? 60A is used after the meter, 40A is used at home. Today, it suddenly tripped

40A can be used in the conventional use of a total of 8 kW (40ax220 V) of electrical power, household generally no problem (unless there are five or six air conditioners, two or three electric water heaters at home to use at the same time, then you need more current it). If there is no electrical appliances or line short circuit, suddenly trip, it is likely to trip this

4X & # 178; Y-1 [6xy-2 (4xy-2) - X & # 178; y] x 1, where x = 1 & # 189;, y = 1

4X & # 178; Y - {6xy-2 (4xy-2) - X & # 178; y} + 1 first remove the small bracket = 4x & # 178; Y - (6xy-8xy + 4-x & # 178; y) + 1, then remove the middle bracket = 4x & # 178; y-6xy + 8xy-4 + X & # 178; y + 1 merge the similar items = 5x & # 178; y + 2xy-3 substitute the data = 5 × (- 1 of 2) &# 178; × 1 + 2 × (- 1 of 2) × 1 -

When the concentration of Na and Al in the solution is pg / cm, the concentration of Na and Al in the solution is 0

According to the reaction equation of sodium and water (2Na + 2H2O = = = 2naoh + H2 ↑), amolna and sufficient water form a / 2 mol H2. Amolnaoh according to the reaction equation of aluminum and sodium hydroxide (2Al + 2naoh + 2H2O = = = = 2naalo2 + 3h2 ↑), amolal and amolnaoh form 3A / 2 mol H2