The Origin of Graphs | History of Mathematics with Luc de Brabandère
How did we come to use graphs, charts and curves to see the patterns in things?
It was thanks to the work of the French mathematician and philosopher, René Descartes, in the 17th Century.
By merging geometry and algebra, Descartes developed the Cartesian Coordinates, which allow us to plot numbers in a visual way to determine trends and tendencies.
Follow Luc de Branbandère on his journey through The History of Maths, where he explores everything from Egyptians measuring with the Sun to modern algorithms for self-driving cars.
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The Cartesian coordinates brought maths into the real world, as a tool that helped scientists to make major discoveries.
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For a long period of time, you had two main streams in mathematics. Geometry came from the Egyptians and the Greeks, and the other one, algebra, came from the Arabic world bringing new concepts like zero, the unknown etc.
One day, a French philosopher Descartes had an idea. He said why don't we merge the two disciplines: geometry and algebra. That is a great idea. In order to do so, he invented something called Cartesian coordinates, which suddenly made something incredible possible. It's possible to see mathematics, to see equations. So, if you take the X and Y, the dot 2.4 sits here and you can see where the dot is, you can visualise things, you can slowly start visualising physics. Galileo said “nature is written in the language of mathematics”, so this tool developed by Descartes became a fantastic possibility for many scientists, including Galileo, because you can draw, you can see, you can picture things.
Let's take another dot, 1.1, and then 3.9. You can put the two dots on the same system, and what you do is slowly draw a curve, and the equation is at any X, you take the power of 2 for Y, and you can slowly draw what we call a parabola, and you can mirror the curve. So suddenly, it was possible to see a parabola. Of course, this was a major breakthrough because in the 17th century, people started to find lots of flaws in physics, astronomy and the parabola, for example, was used as a tool in physics. For example, if you take a table like this and you push a ball and then it falls on the ground, this curve is more or less a parabola. So, it was suddenly possible to calculate, like for a cannonball, exactly the same. An incredible tool for scientists.
Another good example still today. Imagine you want to capture the energy of the Sun. You have rays and those rays are parallel and of course you'd like to have all the rays focusing on the same place. The answer? A parabola, because whatever the distance here, the angle will rush the ray to the focus on the parabola. So, there was another major breakthrough in mathematics. Thanks to Descartes, mathematics suddenly became the ultimate tool for science. Thank you, Mr Descartes.
Next time, we will have a look at paradoxes, maths' blind spots.
Why for example it's impossible to cross a square.
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