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Maths & statistics exercises / French and English lessons

Started by scarface, June 16, 2013, 11:58 PM

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scarface

#60
Tonight, I'm offering a new math exercise:
Can you find a number which added to its inverse equals 2,05?
Maybe a user of the forum can solve it, otherwise I will give you the step-by step solution.

Since nobody was able to find the solution, here it is:

First and foremost, let's put this into equation:
X+1/X=2,05 with X≠0
I guess this was the main problem of humbert to solve this exercise.

Then, let's multiply each term of the equation by X
X²+1=2,05X
Let's solve this equation.
X²-2,05X+1=0   
Here we have to solve a quadratic equation.
Δ=b²-4ac=(-2.05)²-4*1*1=4.2025-4=0.2025
Δ>0 so
X1=(-b-√Δ)/2a=(2.05-√0.2025)/2=(2.05-0.45)/2=1.6/2=0.8
X2=(-b+√Δ)/2a=(2.05+√0.2025)/2=(2.05+0.45)/2=2.5/2=1.25



humbert

Quote from: scarface on October 21, 2022, 11:58 PMCan you find a number which added to its inverse equals 2,05?

I'm not clear what you mean by "added to its inverse". Maybe we call it something else. Give me an example.

scarface

Quote from: humbert on October 23, 2022, 05:39 AM
Quote from: scarface on October 21, 2022, 11:58 PMCan you find a number which added to its inverse equals 2,05?

I'm not clear what you mean by "added to its inverse". Maybe we call it something else. Give me an example.
The inverse of the number "x" is "1/x". Now you almost have the equation that you have to solve.

humbert

Quote from: scarface on October 23, 2022, 01:47 PMThe inverse of the number "x" is "1/x". Now you almost have the equation that you have to solve.

We called it the "reciprocal" in school. Any number x its reciprocal = 1

scarface

Quote from: humbert on October 27, 2022, 05:44 AMWe called it the "reciprocal" in school. Any number x its reciprocal = 1
The reciprocal is another term for the inverse of a number indeed. I think my Math teachers were using this word when I was in preparatory class for high schools.
I'm still waiting for sb to solve this math problem. Otherwise I'll give the solution soon.

Daniil

Guys, I have a question about English language. At my workplace, they teaching us English, for free. But, as far as I know English, sometimes they teach us very strange things. So I need a help of you as native ot almost-native english-speakers.

First of all:
Task
and
answer

Take a look at what I underscribe by red. The phrase is: "Our corporate culture is based on advanced pharmaceutical research by the best minds in Europe." And teacher said to us that that's normal, that's the way how english-speakers can talk about corporate culture. Errm, what? How should I understand this? How corporate culture could be linked with pharmaceutical researches? Or they using meth and LSD in their corporate life??? >:(  ;D

scarface

Quote from: Daniil on November 11, 2022, 12:57 PMTake a look at what I underscribe by red. The phrase is: "Our corporate culture is based on advanced pharmaceutical research by the best minds in Europe." And teacher said to us that that's normal, that's the way how english-speakers can talk about corporate culture. Errm, what? How should I understand this? How corporate culture could be linked with pharmaceutical researches? Or they using meth and LSD in their corporate life??? >:(  ;D

Well, for me it depends on the context. If this sentence is used in the booklet of a pharmaceutical company, it might not be a problem. If this is a car salesman who says that, it's more ambiguous.
PS: I don't know the verb "underscribe", and after further investigation, it's not in my dictionary. You should use "underline" instead.
PS2: Note that your example is not really a phrase, it's a sentence. You should avoid the word "phrase" in English in this case, a phrase is an expression, just a group of words that doesn't convey a complete thought. Note that the English word "sentence" is translated in French by "phrase" by the way...(otherwise the word sentence in French means judgement and is close to the second sense of the English word).

humbert

Quote from: Daniil on November 11, 2022, 12:57 PMGuys, I have a question about English language. At my workplace, they teaching us English, for free. But, as far as I know English, sometimes they teach us very strange things. So I need a help of you as native ot almost-native english-speakers.

I believe I mentioned somewhere else of the forum that written English is an absolute disaster. It's a bastard language which originated after the Norman invasion of England in 1066. It is French mixed with the Norse dialects spoken in Britain at the time. There is no governing body. Americans write it one way, everyone else another way. Sadly the British Empire took their bastard language and spread it all over the world.

From what I've learned so far from trying to learn the Cyrillic alphabet, I'm noticing that the Russian language is very phonetic. Mostly you write like you say it. Spanish and Italian are also like that.

With respect to your question about the strange sentence, is there any way you could ask the author what he meant. Frankly it's not clear to me either.


Daniil

Quote from: scarface on November 11, 2022, 01:11 PMWell, for me it depends on the context. If this sentence is used in the booklet of a pharmaceutical company, it might not be a problem. If this is a car salesman who says that, it's more ambiguous.

Thank you very much for explanation, friend! I'll follow your recommendations!

Quote from: humbert on November 14, 2022, 06:06 AMI believe I mentioned somewhere else of the forum that written English is an absolute disaster. It's a bastard language which originated after the Norman invasion of England in 1066. It is French mixed with the Norse dialects spoken in Britain at the time. There is no governing body. Americans write it one way, everyone else another way. Sadly the British Empire took their bastard language and spread it all over the world.
Well, bastard or not, but it's now a main language of international communications and science. So I must know it well!

BTW, I clearly understand your opinion about English. I can say a lot of similar things about Russian. Today Russian language contains a lot of useless and "official" forms, but, for example, contains not any word for private business. Did you ever hear the theory about that language forming a mentality? Russian language definetly forming russian mentality. I.e., when we could do nothing because we can't even imagine that (have no words for that!), but have a lot of words for hate, suspect and claiming.

Quote from: humbert on November 14, 2022, 06:06 AMWith respect to your question about the strange sentence, is there any way you could ask the author what he meant. Frankly it's not clear to me either.
That's the point! I've asked out teacher about this, she said that this sentence is from a textbook. She said that she'll send it to me via Telegram.

humbert

Quote from: Daniil on November 14, 2022, 01:22 PMBTW, I clearly understand your opinion about English. I can say a lot of similar things about Russian. Today Russian language contains a lot of useless and "official" forms, but, for example, contains not any word for private business. Did you ever hear the theory about that language forming a mentality? Russian language definetly forming russian mentality. I.e., when we could do nothing because we can't even imagine that (have no words for that!), but have a lot of words for hate, suspect and claiming.

I'm not surprised. For 1500 years or longer Russia has been ruled by dictators and despots who controlled everything. In this environment it was impossible for private business to get started. To analogize, languages of many indigenous cultures who live in tropical environments have no word for "snow" or "ice". The word "hurricane" is a loose translation of the indigenous word "huracán" to describe huge tropical storms. The Spaniards imported it because their language had no word for it.

Mostly I was referring to the fact that, unless I'm mistaken, the Russian language is very phonetic. You write it the same way you say it. English is nothing like that.