__L__ := ScientificErrorAnalysis[Quantity]( 1.552, .002 );
__T__ := ScientificErrorAnalysis[Quantity]( 2.510, 0.01 );

__g__ := 4 * Pi^2 * __L__/(__T__^2);

__DerivedError__ := combine( __g__, 'errors' );

__RelativeError__ := ScientificErrorAnalysis[GetError]( __DerivedError__ ) /
                ScientificErrorAnalysis[GetValue]( __DerivedError__ );