Trigonometry Values Pi/10
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|  | (1) |
So we have
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|  | (2) |
and
 | (3) |
| |  | (4) |
| |  | (5) |
 | |  | (6) |
 | |  | (7) |
 | |  | (8) |
 | |  | (9) |
An interesting near-identity is given by
 | (10) |
.See also Decagon, Decagram- Runge-Walsh Theorem
- Running Knot
- Russell's Antinomy
- Russell's Paradox
- Russian Multiplication
- Russian Roulette
- Ryser Formula
- Rényi's Parking Constants
- Rössler Model
- Saalschützian
- Saalschütz's Theorem
- s-Additive Sequence
- Saddle
- Saddle-Node Bifurcation
- Saddle Point (Fixed Point)
- Saddle Point (Function)
- Saddle Point (Game)
- Safarevich Conjecture
- Safe
- Sagitta
- Saint Andrew's Cross
- Saint Anthony's Cross
- Saint Petersburg Paradox
- Sal
- Salamin Formula