When Xiaojun reads a story book, the ratio of the number of pages he has read to the number of pages left is 2:3. Xiaojun's good friend Xiaohui finds that the number of pages he has read is 28 pages less than 4 / 3 of the total number of pages in the story book

When Xiaojun reads a story book, the ratio of the number of pages he has read to the number of pages left is 2:3. Xiaojun's good friend Xiaohui finds that the number of pages he has read is 28 pages less than 4 / 3 of the total number of pages in the story book

Xiao Jun read a 120 page story book, 20% in four days. According to this calculation, how many days will he have to finish reading the remaining pages? (two solutions, one of which is proportional solution)

(1) 20% △ 4 = 5% (1-20%) / 5% = 80% △ 5% = 16 (days) (2) if the remaining pages need to be read in X days, then 20%: 4 = (1-20%): X & nbsp; 0.2:4 = 0.8: X & nbsp; & nbsp; & nbsp; & nbsp; 0.2x = 4 × 0.8 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 0.2x = 3.2 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp

Xiao Jun opened a story book. The ratio of the number of pages he had read to the number of pages left was 2:3. If he read another 60 pages, he would finish the book. How many pages is the book?
fast

60÷3=20
2+3=5
20×5=100

Antonyms and comparative English
White different fat heavy: find the antonym above: find the comparative degree of the following words: Sunny short aesthetic intelligent: heavy long fat going serious

The antonym black same thin light comparative level funnier. Shorter. More aesthetic. More intellectual. Heavier. Fatter. More outgoing. More serious

Application of sine and cosine theorem
1. In the triangle ABC, if AB = 5, BC = 7, ab = 8, then the sum of the maximum angle and the minimum angle of the triangle ABC is
2 in triangle ABC, angles a, B, C satisfy (2a-c) CoSb = bcosc
1. Calculate the angle B
2. If B = 7, a + C = 4, find the area of triangle ABC
It's a process

Question 1: let AB = C, BC = a, CA = B, C ^ 2 + B ^ 2-A ^ 2 = 2bccosa data into cosa = 1 / 2 get a = 60 degrees, because the sum of the maximum angle and minimum angle of triangle ABC B + C = 180A = 120

The formation of the verb ing form

The formation of present participle
(1) In general, adding - ing after the verb to form: work / working, sleep / sleeping, wait / waiting, etc
(2) In the silent - e ending verb, remove E and add - ing: Smile / smile, move / moving, etc
(3) If the verb ends with stressed closed syllable or R syllable and only one consonant letter at the end, double write the consonant letter at the end and add - ing: sit / sitting, plan / planning, refer / referring, occur / occurring, etc
(4) Verbs ending with the letter ie usually change ie to y and add ing: Die / dying, lie / lying, tie / tying, etc
[note] (1) verbs ending with the letter L. if the last syllable is an stressed syllable, you must double write L and add ing, such as control / controlling. But if the last syllable is an unstressed syllable, you can double write L (British English) or not, such as travel / travel (L) ing
(2) There are rules of changing y for nouns into plural, adjectives and adverbs into comparative and superlative, verbs into past tense and past participle, but there is no rule of changing y for present participle
(3) The present participle of the verb "picnics" is "picnicking", not "picnicking"

Please give some examples to illustrate the law of negation
Take the nature, human society and human cognition as the object respectively, and give three examples to have detailed theoretical analysis
Two negations and three stages
Paste and copy again, friends on the first floor, at least you have to see what I'm asking.

The law of negation
Marx and Engels' negation principle of negation comes from Hegel's "positive negative combination" three-stage theory: "due to the development of internal contradictions, the normal things will transition to the negative and become the" anti "stage, which is the first negation; from the negative stage to its negative, it is the negation of negation. After the negation of negation, things return to the" normal "state
Materialist dialectics holds that the development of things is a process connected with a process, and the replacement of the process should be realized through negation. In the long chain of the development of things, after two negations, three stages, namely, affirmation, negation and negation of negation, are shown as a cycle. Therefore, the law of negation of negation reveals the trend and road of the development of things
It should be pointed out that the state of negation after negation of negation is not the original positive state, but a kind of "sublation" after a higher level building. In Lenin's words, it seems to be the reply of the old things on the basis of high level, which is "the progress of content and the return of form"
Materialist dialectics holds that the general trend of the development of things is forward and upward, but the road is tortuous. Lenin called it "spiral upward", Mao Zedong called it "wave forward" and "bright future and tortuous road". The reason why the general trend is forward is that negation is not "abandonment", but "sublation", which is to develop on the basis of affirming a part, The reason why development is tortuous is that the development of things is driven by the internal contradictions and struggles
For example, the process from seed to fruit and then to seed is a process of negation of negation. Another example is the Chinese folk proverb, "when things go against the extreme" is the first negation, and "when things turn out the best" is the negation of negation, Society and Communist society will be public ownership (not the public ownership of material shortage in primitive society, but the public ownership of material abundance after the development of slavery, feudalism and capitalism), which is also a process of negation of negation

What are the plural words or prototypes

People --- people --- deer --- sheep --- fish --- fish
spacecraft

In the triangle ABC, ACOS + bcos = CCOS, then the shape of the triangle?

According to the sine theorem, a / Sina = B / SINB = C / sinc
∵acosA+bcosB=ccosC
∴sinAcosA+sinBcosB=sinCcosC
∴sin2A+sin2B=sin2C=sin(2π-2A-2B)=-sin(2A+2B)
∴0=sin2A+sin2B+sin(2A+2B)
=sin2A+sin2B+sin2Acos2B+sin2Bcos2A
=sin2A(1+cos2B)+sin2B(1+cos2A)
=4sinAcosAcos²B+4sinBcosBcos²A
=4cosAcosBsin(A+B)
∵sin(A+B)=sin(π-C)=sinC>0
Ψ cosa = 0 or CoSb = 0
A = π / 2 or B = π / 2
{△ ABC is a right triangle with a or B hypotenuse

The usage of noun as attributive or (attributive noun) in English

The attributive nouns are usually used to describe the material, purpose, time, place, content and category of the nouns