001

Author: Michael Abbott

README.md

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+# Bhāskara
+
+Provides Bhaskara I's sine approximation formula
+
+```julia
+sinπ(θ) = 16(π-θ)θ / (5π^2 - 4(π-θ)θ) # < 0.1% error, θ ∈ [0,π]
+```
+
+There is also `sin2π(θ)` for `θ ∈ [-π,π]`, and `Bhaskara.sin(θ)` for `θ ∈ 𝐑`,
+by inserting appropriate `mod(,2π)` and `sign()*abs()` bits. 
+
+Similarly `cosπ(θ)` is for `θ ∈ [-π/2,π/2]`, and `Bhaskara.cos(θ)` for `θ ∈ 𝐑`.

src/Bhaskara.jl

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+module Bhaskara
+
+export sinπ, sin2π, cosπ, sind180
+
+
+sinπ(θ) = 16(π-θ)θ / (5π^2 - 4(π-θ)θ)
+
+sin2π(θ) = sign(θ) * sinπ(abs(θ))
+
+sin(θ::T) where T<:Number = sin2π(mod(θ+π, T(2)*π) - π)
+
+
+sind180(x) = 4(180-x)x / (40500 - (180-x)x)
+
+sind360(x) = sign(x) * sin180(abs(x))
+
+sind(x::Number) = sind360(mod(x+180,360)-180)
+
+
+cosπ(θ) = (π^2 - 4θ^2) / (π^2+θ^2)
+
+cos(θ::T) where T<:Number = sin2π(mod(θ+π/T(2), T(2)*π) - π)
+
+
+tan(θ::Number) = sin(θ) / cos(θ)
+
+end # module