I needed the PI constant in C++, and I was lead to the answer that:
const PI = atan(1) * 4
Note that despite involving code, I'm asking this from a mathematics perspective.
I have 2 questions about this:
- Is this an estimation of PI, or should it give me a large degree of accuracy?
- How does this give PI?
On the second point, if I understand
atan correctly, it takes a ratio of two sides, and returns the corresponding angle.
That means that
atan(1) is referring a situation with 2 equal length sides.
I think I'm misunderstanding something though, as
atan(1) gives me
0.7853981633974483, which seems like a very tiny angle.
If anyone can fill in the holes, it would be greatly appreciated.