<![CDATA[Math Is Fun Forum]]> 2018-01-19T12:51:47Z FluxBB http://www.mathisfunforum.com/index.php <![CDATA[Oral puzzles]]> Hi,

#3886. Five cards - the ten, jack, queen, king, and the ace of diamonds, are well-shuffled with their face downwards. One card is then picked up at random.
(i) What is the probability of the card is the queen?
(ii) If the queen is drawn and put aside, what is the probability of the second card picked up is (a) an ace? (b) a queen?

http://www.mathisfunforum.com/profile.php?id=682 2018-01-19T12:51:47Z http://www.mathisfunforum.com/viewtopic.php?id=3144&action=new

#6323. Obtain the zeroes of the polynomial

, if two of its zeroes are -2 and -1.

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<![CDATA[crème de la crème]]> 264) Jimmy Wales

Jimmy is an internet entrepreneur best known for founding the open-content reference site Wikipedia.


Jimmy Wales was born in Huntsville, Alabama, on August 7, 1966. Wales attended graduate school for finance before dropping out to pursue business ventures. In 2001, Wales founded the open-content internet resource Wikipedia, which became the world's largest encyclopedia. Wales also founded the for-profit web-hosting company Wikia, and has advised governments and universities.

Early Life

Jimmy Donal Wales was born in Huntsville, Alabama, on August 7, 1966. He attended a one-room school run by his mother and grandmother through the eighth grade. An intellectually curious child whose education proceeded according to the Montessori system, Wales spent considerable amounts of time reading encyclopedias. He credits this self-directed upbringing with his ability to think creatively.

Wales attended the Randolph preparatory school and studied finance at Auburn University. After graduating, he began a doctoral program in finance at the University of Alabama. Wales transferred to Indiana University before dropping out of school to take a job in a financial services firm.


Wales had been interested in the internet from its earliest days. In 1996, he left his job at the firm to cofound a startup called Bornis. Although the venture was not successful, it motivated Wales to pursue his vision of creating an online encyclopedia. In March 2000, he launched Nupedia—an open-content, peer-moderated reference site. He hired an academic, Larry Sanger, to serve as editor-in-chief.

Sanger learned about wikis in 2001 and Wales agreed to adopt the model. Wikipedia and Nupedia co-existed for a short time, with Wikipedia attracting much more traffic and participation. Without the funding to continue his position, Sanger resigned from both organizations in 2002. Sanger and Wales would later spar publicly over Sanger's role at Wikipedia. While Sanger considers himself a co-founder, Wales claims total conceptual ownership of the enterprise.

The non-profit Wikimedia Foundation, founded by Wales, has overseen the development of Wikipedia since 2003.

Other Ventures

In 2004, Wales and colleague Angela Beesley founded a for-profit internet company called Wikia. He stepped down from his position as CEO in 2009.

Wales began advising the British government on potential open access initiatives in 2012. The goal of the project was to make government-funded research available to taxpayers at no cost. In addition to his paid positions, Wales serves on the advisory boards of a number of academic foundations and research centers.

Personal Life

Wales has been married three times and has two daughters. He has received a number of major awards and honorary degrees from institutions, including Amherst College.

Wales is an outspoken atheist and an adherent of Objectivism, a philosophy popularized by author Ayn Rand. Objectivism privileges individualism, capitalism and reason. He identifies as a libertarian though he is not a supporter of the Libertarian Party.


http://www.mathisfunforum.com/profile.php?id=682 2018-01-19T12:22:15Z http://www.mathisfunforum.com/viewtopic.php?id=22637&action=new
<![CDATA[Breathing Trouble while Meditation]]> George,Y wrote:

Uh it is surprising to find so many mathematicians practice meditation!

People can be spiritual without being religious – http://www.bbc.co.uk/news/magazine-20888141.

http://www.mathisfunforum.com/profile.php?id=217821 2018-01-19T00:57:23Z http://www.mathisfunforum.com/viewtopic.php?id=15007&action=new
<![CDATA[Math]]> hi Kayla,

I will show you what to do for any regular polygon.  This diagram shows a regular pentagon (5 sides).


You can see that lines radiating out from the centre divide the pentagon into 5 equal triangles.

(1) 360  ÷  5 will tell you the angle at the top of one triangle.

(2) The triangle is isosceles so if you subtract the top angle from 180 and divide the result by 2  you'll have the angle at the bottom of the triangle.

(3) The triangle is split in two so that you have a right angled triangle.  You can use basic trig. on this.  (Half the side) x tan(angle at bottom) = height of triangle.  This is the length of the dotted line.

(4) Calculate the area of the triangle using the formula half x base x height.

(5) Multiply this answer by 5 to get the total area of the pentagon.

If you give this method a try and post your answer at each stage I'll check them for you.


http://www.mathisfunforum.com/profile.php?id=67694 2018-01-18T18:47:29Z http://www.mathisfunforum.com/viewtopic.php?id=24209&action=new
<![CDATA[Homework Problems - Please Help!]]> hi Vedanti

Q1.  There will be different numeric answers, depending on the values of a, b and c; so you won't be able to give numeric coordinates for this.  But an answer with a, b and c is possible.

G is the midpoint of FH, and there is a simple formula for its coordinates:

Add together the x coords of F and H and half it.  This is the x coord of G.  y similarly.

Q2. Again there's a formula (for the equation of a circle) that will help here:

where (a,b) is the centre of the circle, and r the radius.

So if you substitute the known values you'll get a pair of simultaneous equations in a and r.  (not b?  why no b?)

So you can work out both (looks like it may be easier to calculate 'a' first).


http://www.mathisfunforum.com/profile.php?id=67694 2018-01-18T08:19:48Z http://www.mathisfunforum.com/viewtopic.php?id=24208&action=new
<![CDATA[Math]]> hi kayla1dance

Well done! That looks good to me. smile


http://www.mathisfunforum.com/profile.php?id=67694 2018-01-17T20:35:40Z http://www.mathisfunforum.com/viewtopic.php?id=24195&action=new
<![CDATA[Miscellany]]> 59) Parkinson's Disease







Parkinson's signs and symptoms may include:





When to see a doctor










Risk factors

Risk factors for Parkinson's disease include:



Physical relation.

Men are more likely to develop Parkinson's disease than are women.





Depression and emotional changes.



Swallowing problems.


Sleep problems and sleep disorders.






You may also experience:

iii) Fatigue. Many people with Parkinson's disease lose energy and experience fatigue, and the cause isn't always known.
v) Physical dysfunction. Some people with Parkinson's disease notice a decrease in physical desire or performance.





http://www.mathisfunforum.com/profile.php?id=682 2018-01-17T12:28:43Z http://www.mathisfunforum.com/viewtopic.php?id=24036&action=new
<![CDATA[simultaneous or single equation?]]> Thanks for the response, so following that thought...

Journey 1

v = 174/t

Journey 2

v+ 0.5 = 174/t-0.4 thus
(t - 0.4)(v + 0.5) = 174

replace v with 174/t

(t - 0.4)(174/t + 0.5) = 174

174 + 0.5t - 348/5t - 0.2 = 174

t/2 -348/5t = 0.2 + 174 - 174

5t^2 - 696
--------------   =  0.2

5t^2 - 696 = 0.2(10t)

5t^2 - 2t -696 = 0

t = 12 or t = -11.6

t cannot be negative so t = 12

v = 174/12
v = 14.5

if v = 15 then t = 174/15
t = 11.6

thus 0.4 of an hour less than Journey 1 or 24 minutes less than Journey 1

Thank you for your response!

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<![CDATA[A little nice puzzle]]> ganesh wrote:

I asked this problem long time back when I was young.

Oh really? Actually I heard this problem from my friend.

http://www.mathisfunforum.com/profile.php?id=213230 2018-01-16T19:29:11Z http://www.mathisfunforum.com/viewtopic.php?id=24206&action=new
<![CDATA[fourier analysis]]> Hi kristijan,

I may not be able to help you fully but this may be of some help.


Today, the subject of Fourier analysis encompasses a vast spectrum of mathematics. In the sciences and engineering, the process of decomposing a function into oscillatory components is often called Fourier analysis, while the operation of rebuilding the function from these pieces is known as Fourier synthesis. For example, determining what component frequencies are present in a musical note would involve computing the Fourier transform of a sampled musical note. One could then re-synthesize the same sound by including the frequency components as revealed in the Fourier analysis. In mathematics, the term Fourier analysis often refers to the study of both operations.

The decomposition process itself is called a Fourier transformation. Its output, the Fourier transform, is often given a more specific name, which depends on the domain and other properties of the function being transformed. Moreover, the original concept of Fourier analysis has been extended over time to apply to more and more abstract and general situations, and the general field is often known as harmonic analysis. Each transform used for analysis has a corresponding inverse transform that can be used for synthesis.


The first three successive partial Fourier series (shown in red) for a square wave (shown in blue). The second half of the course is devoted to Fourier series and Fourier integrals.

http://www.mathisfunforum.com/profile.php?id=682 2018-01-16T11:57:46Z http://www.mathisfunforum.com/viewtopic.php?id=24205&action=new
<![CDATA[Add 13 more and post it forever.]]> i hope im not late
but the number i am sending is
a number that starts and ends in odd numbers
even numbers throughout the non-ends
the middle is 3-(6/2)
and 06 is split evenly

okay i made this too complicated for 30069

http://www.mathisfunforum.com/profile.php?id=218604 2018-01-15T13:34:33Z http://www.mathisfunforum.com/viewtopic.php?id=13484&action=new
<![CDATA[My New Twin Prime Numbers]]> So far there is no solution for p=3 up to a=10,000

http://www.mathisfunforum.com/profile.php?id=184422 2018-01-15T02:26:38Z http://www.mathisfunforum.com/viewtopic.php?id=19254&action=new
<![CDATA[Need help with building a Curriculum]]> Or Kuran online university

http://www.mathisfunforum.com/profile.php?id=3192 2018-01-15T02:10:21Z http://www.mathisfunforum.com/viewtopic.php?id=24192&action=new
<![CDATA[Arithmetic and Geometric Sequences]]> George,Y wrote:

Note the common ratio is a complex number.

It still works, provided the modulus of the common ratio is less than 1.

http://www.mathisfunforum.com/profile.php?id=217821 2018-01-14T11:47:00Z http://www.mathisfunforum.com/viewtopic.php?id=24202&action=new