### Jan Nordgreen

Shared publicly -I was married by a judge. I should have asked for a jury. – Groucho Marx

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Jan Nordgreen

Attended University Of Oslo

Lives in Puerto del Carmen, Lanzarote, Spain

14,868 followers|417,713 views

AboutPosts

I was married by a judge. I should have asked for a jury. – Groucho Marx

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I grew up with six brothers. That’s how I learned to dance – waiting for the bathroom. – Bob Hope

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I think he's melting

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Spring is nature’s way of saying, “Let’s party!” – Robin William

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jan thats true

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The greatest sign of success for a teacher… is to be able to say, “The children are now working as if I did not exist.” – Maria Montessori

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So true, that is best reward too :)

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From a hospital bed

Hernia operation some time ago.

"An inguinal hernia is a protrusion of abdominal-cavity contents through the inguinal canal. They are very common (lifetime risk 27% for men, 3% for women), and their repair is one of the most frequently performed surgical operations." – Wikipedia

https://en.wikipedia.org/wiki/Inguinal_hernia

Yesterday, I had a bilateral inguinal hernia operation. Since the hospital did not have wifi and/or I didn’t take a long my netbook and, maybe more to the point, I didn’t expect the to stay the night there, I could not post a problem.

Now, I am back home and here comes today’s problem a bit late.

When I came to Spain last fall I was granted membership to Spain’s social security system due to my lack of income. What I had in my bank account, a number between epsilon and delta, was never required information. When I got a job in December I got social securitiy membership as part of my job.

My medical expenses for my hernia problem:

Doctor appointment at my medical centre to report the problem. (a)

Doctor appointment with specialist to determine if an operation was called for. (b)

Hospital doctor appointment to determine the exact character of the problem. Here it was detected that I had two hernias, not one. (c)

Hospital blood test, x-ray, heart test for the operation. (d)

Hospital operation and room and food for 24 hours. (e)

Prescribed medicine to be used after the operation. (f)

Removing the metal stitches in a week. (g)

Evaluation by the hospital doctor in ten days. (h)

Estimate a-h. Please note that I have no other medical insurance than the one mentioned above.

I shared room with a waiter who was operated for the same problem. We wondered how it was to live hundred or more years back with this kind of problem. The image at the top gives a hint.

Hernia operation some time ago.

"An inguinal hernia is a protrusion of abdominal-cavity contents through the inguinal canal. They are very common (lifetime risk 27% for men, 3% for women), and their repair is one of the most frequently performed surgical operations." – Wikipedia

https://en.wikipedia.org/wiki/Inguinal_hernia

Yesterday, I had a bilateral inguinal hernia operation. Since the hospital did not have wifi and/or I didn’t take a long my netbook and, maybe more to the point, I didn’t expect the to stay the night there, I could not post a problem.

Now, I am back home and here comes today’s problem a bit late.

When I came to Spain last fall I was granted membership to Spain’s social security system due to my lack of income. What I had in my bank account, a number between epsilon and delta, was never required information. When I got a job in December I got social securitiy membership as part of my job.

My medical expenses for my hernia problem:

Doctor appointment at my medical centre to report the problem. (a)

Doctor appointment with specialist to determine if an operation was called for. (b)

Hospital doctor appointment to determine the exact character of the problem. Here it was detected that I had two hernias, not one. (c)

Hospital blood test, x-ray, heart test for the operation. (d)

Hospital operation and room and food for 24 hours. (e)

Prescribed medicine to be used after the operation. (f)

Removing the metal stitches in a week. (g)

Evaluation by the hospital doctor in ten days. (h)

Estimate a-h. Please note that I have no other medical insurance than the one mentioned above.

I shared room with a waiter who was operated for the same problem. We wondered how it was to live hundred or more years back with this kind of problem. The image at the top gives a hint.

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2 comments

Hopefully they do it in a different way now!

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The other night I ate at a real nice family restaurant. Every table had an argument going. – George Carlin

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The nausea of not understanding

– Why do you look so gloomy?

– What is 2 + 2?

– 4.

– I already know that!

– So, why do you ask?

– If my calculations gave 5 and everybody said it was 4, how would I feel?

– You tell me. How would you feel?

– I would look at my calculations again.

– Seems to be a reasonable idea.

– But, what if I couldn’t find a mistake? How would I feel?

– Like an outcast, like a member of another species?

– Correct! That is how I feel now.

– What is 2 + 2?

– 4.

– So what is the problem?

– dx/dt = 1/x – x/4 where x=1 when t=0. Find x^2 as a function of t.

– Watch your language! This is a family blog.

– I got two answers.

– Good for you!

– WolframAlpha found one.

– That is not so good.

– I found x^2 = 4 + 3*e^(-t/2) or x^2 = 4 – 3*e^(-t/2).

– And Wolfram?

– x^2 = 4 – 3*e^(-t/2).

– Your other solution shouldn’t be part of the domain. Recheck your calculations to realize that your domain is limited.

– This is how I did it

dx/dt = 1/x – x/4

dx/dt = (4 – x^2)/(4x)

int((4x)/(4 – x^2) dx) = int(1 dt)

-2 ln(abs(4 – x^2) = t + c

Since x(0) = 1 it follows that c = -2 ln3

-2 ln(abs(4 – x^2)) = t – 2 ln3

ln(abs(4 – x^2)) = (-t)/2 + ln3

abs(4 – x^2) = 3 e^(-t/2)

So two solutions:

(1) 4 – x^2 = 3e^(-t/2) when 4 – x^2 >= 0

(2) 4 – x^2 = -3e^(-t/2) when 4 – x^2 <= 0

or

(1) x^2 = 4 – 3e^(-t/2) when 4 – x^2 >= 0

(2) x^2 = 4 + 3e^(-t/2) when 4 – x^2 <= 0

– Impressive!

– Thank you for the compliment. But the second solution must be wrong.

– So, find the mistake.

– Are you listening at all?!

– Why do you look so gloomy?

– What is 2 + 2?

– 4.

– I already know that!

– So, why do you ask?

– If my calculations gave 5 and everybody said it was 4, how would I feel?

– You tell me. How would you feel?

– I would look at my calculations again.

– Seems to be a reasonable idea.

– But, what if I couldn’t find a mistake? How would I feel?

– Like an outcast, like a member of another species?

– Correct! That is how I feel now.

– What is 2 + 2?

– 4.

– So what is the problem?

– dx/dt = 1/x – x/4 where x=1 when t=0. Find x^2 as a function of t.

– Watch your language! This is a family blog.

– I got two answers.

– Good for you!

– WolframAlpha found one.

– That is not so good.

– I found x^2 = 4 + 3*e^(-t/2) or x^2 = 4 – 3*e^(-t/2).

– And Wolfram?

– x^2 = 4 – 3*e^(-t/2).

– Your other solution shouldn’t be part of the domain. Recheck your calculations to realize that your domain is limited.

– This is how I did it

dx/dt = 1/x – x/4

dx/dt = (4 – x^2)/(4x)

int((4x)/(4 – x^2) dx) = int(1 dt)

-2 ln(abs(4 – x^2) = t + c

Since x(0) = 1 it follows that c = -2 ln3

-2 ln(abs(4 – x^2)) = t – 2 ln3

ln(abs(4 – x^2)) = (-t)/2 + ln3

abs(4 – x^2) = 3 e^(-t/2)

So two solutions:

(1) 4 – x^2 = 3e^(-t/2) when 4 – x^2 >= 0

(2) 4 – x^2 = -3e^(-t/2) when 4 – x^2 <= 0

or

(1) x^2 = 4 – 3e^(-t/2) when 4 – x^2 >= 0

(2) x^2 = 4 + 3e^(-t/2) when 4 – x^2 <= 0

– Impressive!

– Thank you for the compliment. But the second solution must be wrong.

– So, find the mistake.

– Are you listening at all?!

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Have a hat

– The other night I had a most terrible experience.

– You went to the opera?

– Yes, and after the performance I went to get my top hat.

– You use a top hat?

– Only when I go to the opera.

– So, what happened?

– We were N people in line waiting to get our hat.

– You had a ticket for your hat?

– Yes, but the first person had lost his ticket so he just called out a random number.

– He got his hat without a ticket?

– I don’t know if it was his hat, but he got a hat at least.

– Following his strategy we gave the lady our ticket if the hat was still there, if not we just said a random number.

– Did you get your hat?

– I was the last person in the line.

– So, did you get your hat?

– That’s the question. What were the chances for me getting my hat?

– What were N?

– I wish I knew. The opera was Madame Butterfly by Puccini.

– The other night I had a most terrible experience.

– You went to the opera?

– Yes, and after the performance I went to get my top hat.

– You use a top hat?

– Only when I go to the opera.

– So, what happened?

– We were N people in line waiting to get our hat.

– You had a ticket for your hat?

– Yes, but the first person had lost his ticket so he just called out a random number.

– He got his hat without a ticket?

– I don’t know if it was his hat, but he got a hat at least.

– Following his strategy we gave the lady our ticket if the hat was still there, if not we just said a random number.

– Did you get your hat?

– I was the last person in the line.

– So, did you get your hat?

– That’s the question. What were the chances for me getting my hat?

– What were N?

– I wish I knew. The opera was Madame Butterfly by Puccini.

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hello tony pls add me for chat

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Real problem

– Are you ready for a real problem?

– Ready as ever.

– The fuel tank of a real car has a volume of 64 litres and the fuel tank of a model of it 0.125 litres. How much longer than the model is the real car?

– Does the model have a similar shape to the real car?

– Is the sky blue?

– That is easy, then. 64 * 0.125 = 8. The real car is 8 times as long.

– You never stop to amaze me!

– Are you ready for a real problem?

– Ready as ever.

– The fuel tank of a real car has a volume of 64 litres and the fuel tank of a model of it 0.125 litres. How much longer than the model is the real car?

– Does the model have a similar shape to the real car?

– Is the sky blue?

– That is easy, then. 64 * 0.125 = 8. The real car is 8 times as long.

– You never stop to amaze me!

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Sigh!

“Sometimes I lie awake at night and I ask, “Is life a multiple choice test or is it a true or false test?” … Then a voice comes to me out of the dark and says, “We hate to tell you this but life is a thousand word essay.”

— Charles M. Schulz

Since this blog is far removed from life we ask:

If x^2 – px – q = 0, where p and q are positive integers, which of the following could not equal x^3?

4x + 3

8x + 5

8x + 7

10x + 3

26x + 5

Problem source: UK Senior Mathematical Challenge, Organised by the United Kingdom Mathematics Trust.

“Sometimes I lie awake at night and I ask, “Is life a multiple choice test or is it a true or false test?” … Then a voice comes to me out of the dark and says, “We hate to tell you this but life is a thousand word essay.”

— Charles M. Schulz

Since this blog is far removed from life we ask:

If x^2 – px – q = 0, where p and q are positive integers, which of the following could not equal x^3?

4x + 3

8x + 5

8x + 7

10x + 3

26x + 5

Problem source: UK Senior Mathematical Challenge, Organised by the United Kingdom Mathematics Trust.

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Programming is one of the most difficult branches of applied mathematics; the poorer mathematicians had better remain pure mathematicians. – Edsger Dijkstra

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Communities

30 communities

Education

- University Of OsloMathematics, Computer Science
- University of GeorgiaMathematics Education

Basic Information

Gender

Male

Looking for

Friends, Networking

Relationship

Married

Story

Tagline

I would like to be someone who would like to be me.

Introduction

George Polya, Imre Lakatos, and Søren Kierkegaard are some of my educational heroes.

Bragging rights

I have proven that Black does not always win in Go.

Work

Occupation

Learner and teacher of maths, ICT, patient problem solving, and tolerance.

Skills

12 Jul 2011 - very first post

Places

Currently

Puerto del Carmen, Lanzarote, Spain

Previously

Marbella, Spain - Fuengirola, Malaga, Spain - Puerto de La Cruz, Tenerife, Spain - Halden, Sarpsborg, Hornnes, Norway - Hauge i Dalane, Bjoneroa, Notodden, Norway - Athens, USA - Benalmadena, Los Boliches, Santa Cruz de Tenerife, Spain - Cooperstown, Freeport, Bahamas - George Town, Cayman Island - Tarija, Samaipata, Santa Cruz, Bolivia - Montpellier, France - Ban Chang, Rayong, Thailand

Links