More Writing: Calculus and Area/Volume Calculations of Arbitrary Shapes
I re-read some of my blog posts, and I think I should still be "somewhat occupied with writing," as I had originally said. I should plan more essays and write them out.
Here is an idea I feel comfortable blurting out today. If you have ever wanted to calculate the area of some shape, let's just say in 2-space for simplicity, you might have wondered what mathematical tools you could use to do that.
The main tool is integral calculus, which calculates the area under a curve. You can calculate areas between two different curves, too, which means in general, if you have an enclosed shape, calculus can help you calculate the area of that shape.
I claim, without proof at this time, that any shape that doesn't have any curves can be captured with triangle-components alone. If you have a pentagon, or a straight line, etc., you can include parts of triangles to construct the shape. So that part is easy, even though, e.g., the triangle formed by the line f(x) = |x| is not differentiable. Using piecewise functions, we can surely calculate the area in between two curves when the curves have nothing to them other than straight lines.
The challenge is curves, though. You might say, "We can just use polynomials to capture the different curves." I claim that that might not work, because there are uncountably infinitely many Taylor series. Of course we have regular polynomials of finite degree, and trigonometric curves, like sin and cos curves. At the same time, I believe that there are uncountably infinitely many curves beyond that.
Perhaps we could restrict attention to Taylor series that we could write down with some formula; there are only countably infinitely many of these. It might be the case that the set of all "drawable" curves, in the physical universe, must also be countable. How could we light up even the pixels of the screen in a way that captures truly "uncountable curvature"?
Another interesting facet of this is, we might be able to explore meaningful functions, beyond the trigonometric functions, using Taylor series. In particular, any time we can conceive of a curve that is curvy and not angled that violates the rule of "admitting only finite-degree-polynomial or trigonometric curves", we can consider the possibility of a new type of function that we might wish to study. In general, one great way to explain new functions is to write out power series functions for curves that we know don't conform to finite degree polynomials or trigonometric functions. Upon studying these functions, we might be able to develop a treasure trove of new ideas for functions--and what they might mean, if we pretend that we are discovering a new function the way mathematicians decades ago discovered the trigonometric functions by thinking about triangles.
Ultimately, this is a cool research project for anyone who wants to try to find something new and not necessarily all that useful in basic, undergraduate-level mathematics. I hope you have fun with it if you try it! (I might try it myself someday, but not right now.)
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