# Does there exist a limit for calculating pi?

1. Jul 28, 2010

### polaris12

note that by limit I mean the calculus operation, as in limf(x) as x->a.

I was playing around with numbers earlier today and came up with a limit that gives an exact value for pi. I want to know if others have devised limits that equal to pi, because I am not sure if I am the first because my formula wasn't particularly complicated. If so, please post the formula. I apologize for not posting my limit here, but I hope you will understand why.

2. Jul 28, 2010

### mgb_phys

There are lots of series which calculate pi - given an infinite number of terms.
You can't have an exact value of pi - except in the sense of an infinite series

3. Aug 1, 2010

### sEsposito

You most likely stumbled upon a derivation of one of the many infinite series that calculate out to Pi...

There quite interesting in many cases.

4. Aug 1, 2010

5. Aug 3, 2010

### Coriolis314

Pi is the number of times a diameter goes into its circles circumfrence... you can never have it perfectly accurate. I have a book which shows it to 10,000 digits. As I understant the most accurate super computer gives it to ~10,200. If you looked at a circle with radius 0.5 meters, the diameter would wrap around the circumfrence for 3 meters, 1 decimeter, 4 centimeters, 1 milimeter,... you can keep going and going and going. By deffinition its irrational, it seems like eventually you would get to a perfect spot where the diameter was exactly over the circumfrence without overlapping, alined atom by atom...

6. Aug 3, 2010

### mgb_phys

Not quite, the record is something like 3 trillion digits

7. Aug 6, 2010

8. Aug 6, 2010

### elfboy

waste of a good computer & talent lol

9. Aug 7, 2010

### hotvette

10. Feb 22, 2012

### flisk

I've found some limits for pi:
-limit for x→0 (360/x*tan(x/2))
-limit for x→∞ (x*sin(180/x))

Just found them with simple geometry to divide the circle into multiple triangles. The first limit brings the arc of a triangle to 0, so it'll be very small. The second limit brings the number of triangles to ∞.

Of course limits for pi exist, but as you can see, it's not possible to calculate it exactly. You can only approach the correct value, in this case by measuring/caculate the sin() or tan() of a very small arc.

edit: i've used degrees.

Last edited: Feb 22, 2012
11. Feb 22, 2012

### HallsofIvy

Here's an obvious sequence whose limit is $\pi$:
3, 3.1, 3.14, 3.141, 3.1415, 3.14159, 3.141592, ... !