Hi all, this is my first post here and I wanted to run something by people who are more knowledgeable than I. In the past couple days I've decided that I need to teach myself more advanced mathmatics as it is of great importance to my studies in physics, astronomy and biology. In school we never went past algebra 1 and geometry and that has proven to be a hindrance. So I decided to brush up on the basic math that I learned in school and then move on to more advanced maths. I decided to make up a bunch of problems to solve while waiting for my books to arrive and I ran into my old nemesis, finding square roots of large numbers. I was taught prime factorization, which didn't work for this number, and the Babylonian Method, which can yield accurate results depending on the accuracy of your initial estimate and how many times you're willing to run the equation. What I wanted was an equation that used simple math and a known number instead of an assumed estimate (that must be high in the case of the Babylonian Method) that didn't have to be high or low that would yeald an equally/greater accurate estimate of the square as does the BM, and would only have to be run once. I realize this simple mathmatics compared to what is normally discussed here, so I apologize, and also please forgive me if my terminology isn't quite correct. What I came up with was
√S≈((S/2)/(e/2)+e)/2
in this S is the number we are trying to find the sqaure of and e is the closest perfect square regardless of weather it is high or low.
For exaple, using 1,863 the number I was initially trying to find the sqaure of, we know that the closest perfect sqaure is 43. So it would look like this
√1,863≈((1863/2)/(43/2)+43)/2
√1,863≈((931.5)/(21.5)+43)/2
√1,863≈(43.325+43)/2
√1,863≈ 86.325/2
√1,863≈ 43.163
Actual square of 1863=43.1624
so the estimate it yielded was very close. I've run a bunch of numbers through it both large and small and so far it appears to give better estimates than the BM (depending on the accuracy of your initial high estimate and number of times you run it through the equation) and without the requirement that the estimate is high, and also we don't have to make an initial estimate ourselves as the starting estimate is fixed for us by the nature of the equation.
What do you guys think? Is there something I've missed or perhaps is there an easier equation like it that I am not familiar with?
Thanks!
Sorry left out a couple words in my haste lol. E is the closest perfect square root.