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If the function f (x) defined on [a, b] is greater than 0, then its definite integral on [a, b] must be greater than 0? May it be equal to 0? Your answer is incorrect, because f (x) is not necessarily a continuous function. I already know how to prove it It's my first time to ask a question and see how quickly you reply to me,
Must be greater than 0!
It is proved that there must be a number a on [a, b] by using the integral mean value theorem, such that:
Integral [f (x) * DX] = f (a) * (B-A)
Obviously, f (a) > 0, B-A > 0, so the integral value is > 0
It's over
The problem of definite integral of periodic function
Let f (x) be a continuous function defined on R with t as period and a as any constant. It is proved that the definite integral of F (x) from a to a + T = the definite integral of F (x) from 0 to t
Just change the money
∫ [a, a + T] f (x) DX such that u = x-a, Du = DX
= ∫[0,T] f(u) du
= ∫[0,T] f(x) dx
7.2 * 4.5 * 9.3 / (1.8 * 1.5 * 3.1) simple calculation
7.2*4.5*9.3/（1.8*1.5*3.1）=7.2/1.8 *4.5/1.5 *9.3/3.1=4*3*3=36
In 2008, the total amount of wastewater (including industrial wastewater and urban domestic sewage) discharged in China was about 57.2 billion tons, and the discharge standard rate was about 72%, of which the discharge standard rate of industrial wastewater was about 92%, and the discharge standard rate of urban domestic sewage was about 57%? (the result is accurate to 100 million tons) (Note: the standard rate of wastewater discharge refers to the percentage of the quantity of wastewater discharged and the total quantity)
Suppose the discharge of industrial waste water and urban domestic sewage in 2008 are x billion tons and Y billion tons respectively. According to the meaning of the title, the solution of X + y = 57292% x + 57% y = 572 × 72% is x = 17167y = 2288717167 ≈ 24522887 ≈ 327. A: the discharge of industrial waste water and urban domestic sewage in 2008 is about 24.5 billion tons and 32.7 billion tons respectively
The sister and brother are going to go east from the park gate along the road. They want to go west from the park gate along the road when they go home. They discuss whether they want to go home first to drive to a place to save time or directly walk east from the park gate to a place to save time, Q: how many meters is the distance from the park gate to their home?
To: Thank you very much!
Reply within 48 hours:
Reply within 15 days:
(the initial setting is 5 points,: - D)
Sister and brother are going to go east from the park gate along the road to a certain place. They want to go west from the park gate along the road. They discuss whether they want to go home first and drive to a certain place to save time, or walk directly from the park gate to a certain place to save time
423×925×334− 245×0.423×125=______ ．
423 × 925 × 334-245 × 0.432 × 125 = 423 × 925 × 334-245 × 423 × 0.125; = (925 × 154-145 × 18) × 423; = (2720 − 720) × 423; = 1 × 423; = 423; so the answer is: 423
The current price of an Andersen fairy tale is one sixth lower than the original price. The original price is 4 yuan higher than the current price. How much is the original price?
If the original price is x yuan, the current price is (1-1 / 6) x - (1-1 / 6) x = 4 x = 24, and the original price is 24 yuan
It's not difficult to find the English cardinal numbers of 20, 30, 40, 50, 60, 70, 80, 90100,
twenty thirty forty fifty sixty seventy eighty ninety hundred
Let a > 0b > 0C > 0 and a + B + C = 1 prove that (1 / a minus 1 (1 / b minus 1) (1 / C minus 1) is greater than or equal to 8
Acute acridine
(1 / A-1) (1 / B-1) (1 / C-1) = [(1-A) / a] [(1-B) / b] [(1-C) / C] = [(B + C) / a] [(c + a) / b] [(a + b) / C], which is proved by the mean inequality: (a + b) (B + C) (c + a) > = [2 √ (BC)] * [2 √ (AC)] * [2 √ (AB)] = 8abc, so (1 / A-1) (1 / B-1) (1 / C-1) > = (8abc) / (ABC) = 8
English: are the following sentences right or wrong? Correct them
1)She drinks tea three time a day,
2)Chat shows always are boring.
3)He usually gets up at seven o'clock.
4)My mother watches sometimes football.
5)I buy a newspaper one time a week,
6)Susan ever hardly wears black.
7)French homework is never interesting.
2) chat shows always are (are always) boring. 3) he usually gets up at seven o'clock
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