Interactive rectangular hyperbola (unit-elastic demand curve) e = 1 M′ P′ T′ O Quantity Price M 2.0 P $6.00 T $12.00 P = $6.00, Q = 2.0 → market value = $12.00. Slide anywhere: price × quantity always equals $12 --a rectangular hyperbola is unit-elastic (e = 1) everywhere.