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update #39

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2 changes: 1 addition & 1 deletion docs/src/guide/derived.md
Original file line number Diff line number Diff line change
Expand Up @@ -78,7 +78,7 @@ Analogously, spatial period and frequency are [related by](https://en.wikipedia.
between wavelength `λ` (`𝐋`, `m`), wavenumber `ν` (`1/𝐋`, `1/m`), and angular wavenumber `k` (`𝐀/𝐋`, `rad/m`).
Additionally an angular period and angular wavelength can be defined analogously as the reciprocal of angular frequency and angular wavenumber.

![Diagram showing graphically the relationships between the various properties of harmonic waves: frequency, period, wavelength, angular frequency, and wavenumber.](../assets/Commutative_diagram_of_harmonic_wave_properties.svg
![Diagram showing graphically the relationships between the various properties of harmonic waves: frequency, period, wavelength, angular frequency, and wavenumber.](../assets/Commutative_diagram_of_harmonic_wave_properties.svg)\
*image-source: Waldir, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons*

*DimensionfulAngles.jl* provides [`Periodic`](@ref) a [UnitfulEquivalences.jl](https://sostock.github.io/UnitfulEquivalences.jl/stable/) `Equivalence` to convert between temporal or spatial period, frequency, angular frequency, and angular period of a periodic response.
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33 changes: 25 additions & 8 deletions docs/src/proposed.md
Original file line number Diff line number Diff line change
Expand Up @@ -10,26 +10,43 @@ different, but most (i) include angle as a base dimension, (ii) use a "fundament
constant, typically equal to one radian, to modify the equations of physics, and (iii)
define solid angle as a derived dimension equal to angle squared.
The different proposals, however, take different approaches to which equations or
quantity units to modify.
quantity units to modify.
One exception not considered here is a class of proposals that define a new dimension for *radius length* rather than for *angle*.

Some examples of how common equations would be modified in such systems, using ``θ₀=1rad``:

- Trigonometric functions:
- Trigonometric & exponential functions:

+ ``cos(θ) → cos(θ/θ₀)``
+ ``cos(ωt+φ) → cos([ωt+φ]/θ₀)``
+ ``Aℯⁱᶿ → Aℯ^[iθ/θ₀]``

- Angular frequency and frequency:
- Angular frequency and angular wave number:

+ ``ω=2πf → ω=2πfθ₀``
- Arc length ``s`` and other kinematic equations:
+ ``k=2π/λ → k=2πθ₀/λ``

- Arc length and sector area:

+ ``s=rθ → s=rθ/θ₀``
- For dynamic equations there's more variability between the different proposals.
As an example, [Quincey_2021](@cite) would modify torque (and its unit) while leaving the units of work intact, as
+ ``A=½r²θ → A=½r²θ/θ₀``

- Solid angles
+ ``Ω=A/r² → Ω=Aθ₀²/r²``

- kinematic equations:

+ ``v=rω → v=rω/θ₀``
+ ``a=rω² → a=rω²/θ₀²``

- For dynamic equations, there's more variability between the different proposals.
As an example, [Quincey_2021](@cite) would modify the units of torque and moment of inertia while leaving the units of work and energy intact.

+ ``T=(𝐫×𝐅) → T=(𝐫×𝐅)/θ₀``
+ ``W=Tθ``
+ ``T=(𝐫×𝐅) → T=(𝐫×𝐅)/θ₀`` (torque, new units: ``J/s``)
+ ``I=Σ(mᵢ⋅rᵢ)/θ₀²`` (moment of inertia, new units: ``kg⋅m²/rad²``)
+ ``L=Iω=(𝐫x𝐩)/θ₀`` (angular momentum, new units: ``J/(rad/s)``)
+ ``W=Tθ`` (work)
+ ``E=½Iω²`` (kinetic energy)

## *DimensionfulAngles.jl*'s relation to these proposals

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