Add for cos

Author: jishnub

src/dense.jl

@@ -1116,7 +1116,8 @@ function cos(A::AbstractMatrix{<:Real})
     if isdiag(A)
         return applydiagonal(cos, A)
     elseif issymmetric(A)
-        return copytri!(parent(cos(Symmetric(A))), 'U')
+        P = parent(cos(Symmetric(A)))
+        return copytri_maybe_inplace(P, 'U')
     end
     M = im .* float.(A)
     return real(exp_maybe_inplace(M))
@@ -1125,7 +1126,8 @@ function cos(A::AbstractMatrix{<:Complex})
     if isdiag(A)
         return applydiagonal(cos, A)
     elseif ishermitian(A)
-        return copytri!(parent(cos(Hermitian(A))), 'U', true)
+        P = parent(cos(Hermitian(A)))
+        return copytri_maybe_inplace(P, 'U', true)
     end
     M = im .* float.(A)
     N = -M