Add docs.

doc/stdlib/linalg.rst

@@ -580,9 +580,9 @@ Linear algebra functions in Julia are largely implemented by calling functions f
 
  Computes the solution ``X`` to the Sylvester equation ``AX + XB + C = 0``, where ``A``, ``B`` and ``C`` have compatible dimensions and ``A`` and ``-B`` have no eigenvalues with equal real part.
 
-.. function:: issym(A) -> Bool
+.. function:: issym(A, [tol=1e-10]) -> Bool
 
- Test whether a matrix is symmetric.
+ Test whether a matrix is symmetric. Tol is only used for arrays of FlotingPoint or ``Complex{T<:FlotingPoint}`` numbers, where it tests ``norm(A - A.', Inf) < tol*norm(A,Inf)``.
 
 .. function:: isposdef(A) -> Bool
 
@@ -600,9 +600,9 @@ Linear algebra functions in Julia are largely implemented by calling functions f
 
  Test whether a matrix is upper triangular.
 
-.. function:: ishermitian(A) -> Bool
+.. function:: ishermitian(A, [tol=1e-10]) -> Bool
 
- Test whether a matrix is Hermitian.
+ Test whether a matrix is Hermitian. Tol is only used for arrays of FlotingPoint or ``Complex{T<:FlotingPoint}`` numbers, where it tests ``norm(A - A', Inf) < tol*norm(A,Inf)``.
 
 .. function:: transpose(A)