IntMath Newsletter: vision, wealth and slopes

By Murray Bourne, 28 Oct 2010

28 Oct 2010

In this Newsletter:

1. Math application: 20/20 vision and trigonometry
2. Math application: Statistics and wealth distribution
3. Math tip: The slope of the 3 main trigonometric curves
4. Friday math movies: Math education and cell animations
6. Final thought: Dealing with mistakes

Welcome to the hundreds of new people who have signed up for the IntMath Newsletter!

1. What does 20/20 vision mean?

Suitable for: Everyone. This article ties trigonometric concepts into something that's important for all of us - good vision.


We often hear the expression 20/20 vision. What do the 2 numbers mean?

What does 20/20 vision mean?

2. Singapore wealth - mean and median?

Suitable for: Everyone. The wealth distribution of a country affects its stability, so this is an important application of statistics.


When we have a distribution with a high mean but a low median, what does it look like?

Singapore wealth - mean and median?

3. Explore the slope of the sin, cos and tan curves

Suitable for: Everyone. The slope of a straight line is easy - find vertical rise and divide by horizontal run. But what is the slope of a curve? This is an important concept and worth thinking about, even if you've never heard of calculus yet.

I broke this up into 3 separate articles to make it more digestible.

sine curve

a. Sine curve

Use an interactive graph to explore how the slope of sine x changes as x changes.

Explore the slope of the sin curve


cosine curve slope investigation

b. Cosine curve

What is the value of the slope of the cosine curve? Use an interactive graph to investigate it.

Explore the slope of the cos curve


slope of the tan curve

c. Tangent curve

You can investigate the slope of the tan curve using an interactive graph.

Explore the slope of the tan curve

4. Friday math movies

Suitable for: Everyone.

a. Arthur Benjamin's formula for changing math education

arthur benjamin

What math topic is most useful for people in their "real life"?

Friday math movie: Arthur Benjamin's formula for changing math education

b. David Bolinsky animates a cell

animate cell

Our bodies truly are beautiful and amazing.

Friday math movie: David Bolinsky animates a cell

5. Final thought: Dealing with mistakes

Donald Trump had a very successful career in real estate until he ran into serious financial difficulties during the 1990s and basically went broke. He has since recovered and is now worth around US$2.6 billion.

The following quote by Trump applies to all math students!

"Make your mistakes work for you by learning from them."

Donald Trump

Until next time, enjoy whatever you learn.

See the 6 Comments below.

6 Comments on “IntMath Newsletter: vision, wealth and slopes”

  1. DEPR says:

    The newsletter was very informative, specially the 20/20 vision and Singapore statistics....But didn't show the tangents of sinx, cosx and tanx by
    Anyhow keep it up and very nice work.

  2. Janet Teeguarden says:

    I was sorry to see that two movies were listed, but that only one movie was shown (twice). I liked Arthur Benjamin's message, but the animation of a cell would be nice to see too. That link goes back to Benjamin again.

  3. Murray says:

    @DEPR: The jsxgraph interactive needs Firefox or Safari browser (it does not work reliably in Internet Explorer). Also, you need to view it on the original page (if you are reading a feed of the post through an aggregator it won't play nicely).

    @Janet: Oops - a copy-paste issue. The link on the image was fine, but the text link was wrong. I have fixed it in the post. It's a great video!

  4. HIWOT says:

    i passed the coarse with a good result thanks for all you have done to me

  5. Murray says:

    Hey, that's great, Hiwot. Congratulations!


    I am very very happy with your math article,it is wealthy informative site for math learning.

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