**Google+ reshared post**

Adding the first n cubes, in an animationIf you add up the first n numbers and square the result, this produces the same answer as adding the first n cubes. This animation by

Hydrodiumon tumblr gives a stunningly good illustration of this identity.The graphic shows the case n=5. In this case, the sum of the first 5 natural numbers is 1+2+3+4+5=15, which squares to 15×15=225. On the other hand, the sum of the first n cubes is (1x1x1)+(2x2x2)+(3x3x3)+(4x4x4)+(5x5x5)=1+8+27+64+125, which also adds up to 225. There is nothing special about the number 5 here: an analogous identity holds for any other positive integer, and it can be illustrated by a similar animation.

At this point, the moderators of the arXiv preprint server would rightly accuse me of “substantial text overlap” with an earlier post. Yes, I’ve posted about this before (https://plus.google.com/101584889282878921052/posts/WqimoVTZWL3) but this animation does an even better job of showing how everything fits together.

The animation comes from

Hydrodium’s Graphical MathLandat http://hyrodium.tumblr.com/post/94237657514/inspired-by-this-twocubes-post-and-asked-to-make

I found it via the blogVisualizing Math(http://visualizingmath.tumblr.com/) which in turn I found via +W Younes. There are a lot of very interesting posts onVisualizing Math. However, I might be a bit biased in saying that, because I found two of my own recent posts reshared there (with attribution).

Importé de Google+