Fix a sign error in documentation

doc/src/manual/noteworthy-differences.md

@@ -19,7 +19,7 @@ may trip up Julia users accustomed to MATLAB:
   * The imaginary unit `sqrt(-1)` is represented in Julia as [`im`](@ref), not `i` or `j` as in MATLAB.
   * In Julia, literal numbers without a decimal point (such as `42`) create integers instead of floating
     point numbers. As a result, some operations can throw
-    a domain error if they expect a float; for example, `julia> a = 1; 2^a` throws a domain error, as the
+    a domain error if they expect a float; for example, `julia> a = -1; 2^a` throws a domain error, as the
     result is not an integer (see [the FAQ entry on domain errors](@ref faq-domain-errors) for details).
   * In Julia, multiple values are returned and assigned as tuples, e.g. `(a, b) = (1, 2)` or `a, b = 1, 2`.
     MATLAB's `nargout`, which is often used in MATLAB to do optional work based on the number of returned