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cospi

Compute the cosine of π*x, where x expressed in half-revolutions.

Base.Math.cospi — Function
cospi(x)

Compute $\cos(\pi x)$ more accurately than cos(pi*x), especially for large x.

source

Methods

julia> methods(cospi, (Any,), [Base, Base.Math, Base.MathConstants, Base.MPFR])# 7 methods for generic function "cospi" from Base.Math:
 [1] cospi(x::BigFloat)
     @ Base.MPFR mpfr.jl:860
 [2] cospi(::Missing)
     @ math.jl:1533
 [3] cospi(x::T) where T<:Union{Float16, Float32, Float64}
     @ special/trig.jl:821
 [4] cospi(x::AbstractFloat)
     @ special/trig.jl:928
 [5] cospi(x::Integer)
     @ special/trig.jl:923
 [6] cospi(x::Real)
     @ math.jl:1528
 [7] cospi(z::Complex{T}) where T
     @ special/trig.jl:966

Examples

Real Numbers

julia> cospi(0)
1.0

julia> cospi(-0.0)
1.0

julia> cospi(0.5)
0.0

julia> cospi(1)
-1.0

Complex

julia> cospi(0+0im)
1.0 - 0.0im

Tips

See Also

cos

Extended Inputs

Tech Notes

  • cospi(::Real): by pure julia
  • cospi(::BigFloat): by MPFR

Version History

Introduced in Julia v1.0 (2018)