Returns a {@code Complex} whose value is {@code this * factor}. Implements preliminary checks for {@code NaN} and infinity followed bythe definitional formula:
(a + bi)(c + di) = (ac - bd) + (ad + bc)i
Returns {@link #NaN} if either {@code this} or {@code factor} has one ormore {@code NaN} parts.
Returns {@link #INF} if neither {@code this} nor {@code factor} has oneor more {@code NaN} parts and if either {@code this} or {@code factor}has one or more infinite parts (same result is returned regardless of the sign of the components).
Returns finite values in components of the result per the definitional formula in all remaining cases.
@param factor value to be multiplied by this {@code Complex}.
@return {@code this * factor}.
@throws NullArgumentException if {@code factor} is {@code null}.