CalculusWithJuliaNotes.jl/CwJ/TODO/arrows.md

This is really just

plot!([0,cos(θ)],[0,sin(θ)], arrow=true)

https://stackoverflow.com/questions/58219191/drawing-an-arrow-with-specified-direction-on-a-point-in-scatter-plot-in-julia

https://github.com/m3g/CKP/blob/master/disciplina/codes/velocities.jl

using Plots using LaTeXStrings

function arch(θ₁,θ₂;radius=1.,Δθ=1.) θ₁ = πθ₁/180 θ₂ = πθ₂/180 Δθ = πΔθ/180 l = round(Int,(θ₂-θ₁)/Δθ) x = zeros(l) y = zeros(l) for i in 1:l θ = θ₁ + iΔθ x[i] = radiuscos(θ) y[i] = radiussin(θ) end return x, y end

plot()

x, y = arch(0,360) plot(x,y,seriestype=:shape,label=““,alpha=0.5)

x, y = arch(0,360,radius=0.95) plot!(x,y,seriestype=:shape,label=““,fillcolor=:white)

x, y = arch(0,360,radius=0.7) plot!(x,y,seriestype=:shape,label=““,alpha=0.5,fillcolor=:red)

x, y = arch(0,360,radius=0.65) plot!(x,y,seriestype=:shape,label=““,fillcolor=:white)

plot!([0,0],[0,1.1],arrow=true,color=:black,linewidth=2,label=““) plot!([0,1.1],[0,0],arrow=true,color=:black,linewidth=2,label=”“)

x, y = arch(15,16,radius=0.65) plot!([0,x[1]],[0,y[1]],arrow=true,color=:black,linewidth=1,label=““)

x, y = arch(35,36,radius=0.95) plot!([0,x[1]],[0,y[1]],arrow=true,color=:black,linewidth=1,label=““)

plot!(draw_arrow=true) plot!(showaxis=:no,ticks=nothing,xlim=[-0.1,1.1],ylim=[-0.1,1.1],) plot!(xlabel=“x”,ylabel=“y”,size=(400,400))

annotate!(0.58,-0.07,text(L”v_1”,10)) annotate!(0.88,-0.07,text(L”v_2”,10))

savefig(“./velocities.pdf”)