Hi, Im trying to plot my Chebyshev approximation

```
using Printf
using Plots
pyplot()
mutable struct Cheb_struct
c::Vector{Float64}
min::Float64
max::Float64
end
function cheb_coeff(min::Float64, max::Float64, n::Int, fn::Function)::Cheb_struct
struc = Cheb_struct(Vector{Float64}(undef,n), min, max)
f = Vector{Float64}(undef,n)
p = Vector{Float64}(undef,n)
max_plus_min = (max + min) / 2
max_minus_min = (max - min) / 2
for k in 0:n-1
p[k+1] = pi * ((k+1) - 0.5) / n
f[k+1] = fn(max_plus_min + cos(p[k+1])*max_minus_min)
end
n2 = 2 / n
for j in 0:n-1
s = 0
for i in 0:n-1
s += f[i+1]*cos(j*p[i+1])
struc.c[j+1] = s * n2
end
end
return struc
end
function approximate(struc::Cheb_struct, x::Float64)::Float64
x1 = (2*x - struc.max - struc.min) / (struc.max - struc.min)
x2 = 2*x1
t = s = 0
for j in length(struc.c):-1:2
pom = s
s = x2 * s - t + struc.c[j]
t = pom
end
return (x1 * s - t + struc.c[1] / 2)
end
fn = sin
struc = cheb_coeff(0.0, 1.0, 10, fn)
println("coeff:")
for i in struc.c
@printf("% .15f\n", i)
end
println("\n x eval approx eval-approx")
for x in struc.min:0.1:struc.max
ev= fn(x)
approx= approximate(struc, x)
@printf("%12.8f %12.8f %12.8f % .3e\n", x,ev, approx, ev-approx)
p =plot(ev,approx)
display(p)
end
```

But I´m getting error:

```
ERROR: LoadError: Cannot convert Float64 to series data for plotting
Stacktrace:
[1] error(::String) at .\error.jl:33
[2] prepareSeriesData(::Float64) at C:\Users\wunsc\.julia\packages\Plots\Ih71u\src\series.jl:13
[3] convertToAnyVector(::Float64) at C:\Users\wunsc\.julia\packages\Plots\Ih71u\src\series.jl:24
[4] macro expansion at C:\Users\wunsc\.julia\packages\Plots\Ih71u\src\series.jl:113 [inlined]
[5] apply_recipe(::Dict{Symbol,Any}, ::Type{Plots.SliceIt}, ::Float64, ::Float64, ::Nothing) at C:\Users\wunsc\.julia\packages\RecipesBase\zBoFG\src\RecipesBase.jl:275
[6] _process_userrecipes(::Plots.Plot{Plots.PyPlotBackend}, ::Dict{Symbol,Any}, ::Tuple{Float64,Float64}) at C:\Users\wunsc\.julia\packages\Plots\Ih71u\src\pipeline.jl:83
[7] _plot!(::Plots.Plot{Plots.PyPlotBackend}, ::Dict{Symbol,Any}, ::Tuple{Float64,Float64}) at C:\Users\wunsc\.julia\packages\Plots\Ih71u\src\plot.jl:178
[8] #plot#133(::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}, ::typeof(plot), ::Float64, ::Vararg{Float64,N} where N) at C:\Users\wunsc\.julia\packages\Plots\Ih71u\src\plot.jl:57
[9] plot(::Float64, ::Float64) at C:\Users\wunsc\.julia\packages\Plots\Ih71u\src\plot.jl:51
[10] top-level scope at C:\Users\wunsc\Desktop\Julia\test.jl:57
[11] include at .\boot.jl:328 [inlined]
[12] include_relative(::Module, ::String) at .\loading.jl:1094
[13] include(::Module, ::String) at .\Base.jl:31
[14] include(::String) at .\client.jl:431
[15] top-level scope at REPL[2]:1
in expression starting at C:\Users\wunsc\Desktop\Julia\test.jl:53
```

I would be very grateful if someone could help me to plot these two functions.