Given the function f (x) = 1 + ln (x + 1) / x, the domain of function definition is obtained

Given the function f (x) = 1 + ln (x + 1) / x, the domain of function definition is obtained

From ln (x + 1), we can get x + 1 ＞ 0 and X ＞ - 1
X is the denominator, so it is not equal to 0
The domain is x ＞ - 1 and X ≠ 0

The mathematical problem is a quadratic equation of one variable, and the speed is online
1. It is known that the square + (4m + 1) x + 2m-1 of the quadratic equation of one variable x = 0
(1) It is proved that no matter it is any real number, the equation always has two unequal real roots
(2) If two of the equations are x1, X2 and satisfy 1 / X1 + 1 / x2 = - 1 / 2, find the value of M
The process should be detailed

(1) According to Δ = B & # 178; - 4ac Δ = (4m + 1) &# 178; - 4 * (2m-1) = 16m & # 178; + 8 > 0, no matter m is any real number, the equation always has two unequal real roots. (2) according to Weida's formula, X1 + x2 = - B / A, X1 * x2 = C / ax1 + x2 = - 4m-1, X1 * x2 = 2m-11 / X1 + 1 / X2, after general division, X1 + x2 / X1 * x2 = -

The original price of a commodity sold in a store is m yuan. There are two price adjustment schemes as follows: one is to increase the price by 10%, and then reduce the price by 10%; the other is to reduce the price by 10%, and then increase the price by 10%. (1) are the results of price adjustment by these two schemes the same? Is the result of price adjustment restored to the original price? (2) The two price adjustment schemes are changed as follows: one is to increase the price by 20% first and then reduce the price by 20% on this basis; the other is to reduce the price by 20% first and then increase the price by 20% on this basis. What is the result? (3) Can you sum up any rules?

Decomposition factor: the square of 16-a + the square of 4ab-4b

An algebra problem!
A-B = 1 / 5, a & sup2; + B & sup2; = 51 / 25, find the power of (AB)

（a-b）²=a²+b²-2ab=1/25
And a & sup2; + B & sup2; = 51 / 25
So 2Ab = 50 / 25 = 2
So AB = 1, so the power of (AB) is 1

Why is it said that "abstract labor forms the value entity of commodity"?

Abstract labor forms the value entity of commodity, because the transformation of heterogeneous concrete labor into homogeneous abstract labor is determined by commodity economic relations, and the value entity is abstract human labor. Abstract labor is the only source of forming commodity value, which does not contain any atom of non labor natural material

A three digit number is 693 larger than the original number. If you transpose the ten digit number and the one digit number, all the numbers are 54 larger than the original number, then find the three
The number obtained is 693 larger than the original number. If the number of ten digits is swapped with the number of one digit, all the numbers are 54 larger than the original number, then the three digits can be obtained

There are two groups in line with the meaning of this question
182-128=54
821-128=693
293-239=54
932-239=693
Therefore, the original three digits should be 128 or 239

Several mathematics problems in the second semester of the first year of junior high school
1. In the quadrilateral ABCD, ∠ a = ∠ C = 90 °, be and DF divide ∠ ABC and ∠ ADC equally, judge whether be and DF are parallel, and explain the reason
2. After a quadrilateral paper is folded along EF, the points D and C fall on the positions d 'and C' respectively. If ∠ AED '= 50 ° and ∠ C + ∠ d = 170 °, the degree of ∠ EFC' is calculated
Speed!

BE//DF
reason:
∵∠A=∠C=90°.
∴∠ADF+∠FDE+∠FBE+∠EBC=180°
And ∵ be and DF divide ∵ ABC and ∵ ADC equally
∴2∠FDE+2∠EBC=180°
∠FDE+∠EBC=180÷2=90°
∵∠C=90°
∴∠BEC+∠EBC=180-90=90°,
■ ∠ FDE = ∠ bec (equivalent substitution)
Ψ be / / DF (the same position angle, two lines parallel)
Because ∠ AED '= 50
So ∠ d'ef = ∠ fed = (180-50) / 2 = 65
In the quadrilateral efcd ', C, + CFE + fed = 360
So ∠ d '+ ∠ C' = 360 - (∠ Fed '+ ∠ c'fe)
=360-170
=190
And because ∠ d'ef + ∠ EFC = 190
So ∠ EFC = 190 - d'ef = 190-65 = 125
So ∠ EFC '= 125

As shown in the figure, in &; ABCD, extend CD to e, make de = CD, connect be, intersect ad at point F, intersect AC at point g. (1) prove: AF = DF;

From ad ‖ BC, ed = CD,
D is the midpoint of EC
FD is the median of △ EBC,
∴FD=（1/2）BC,
And ad = BC,
∴FD=（1/2）AD,
That is, f is the midpoint of AD,
AF = FD

Eight and twenty-three seventeen + five and one-quarter minus six and twenty-three seventeen + 0.75

75 = 8 + 17 / 23 + 5 + 1 / 4 minus 6 + 17 / 23 + 0.75 = 8 + 17 / 23 + 5 + 1 / 4-6-17 / 23 + 3 / 4 = (8 + 5-6) + (17 / 23-17 / 23) + (1 / 4 + 3 / 4) = 7 + 0 + 1 = 8, please click the "adopt answer" button below to send us a little red flower for encouragement!