11. The method of claim 1 , wherein the calculator processes waveforms used to simulate an electronic circuit.
1. A method of displaying in a calculator, comprising: receiving a first mathematical expression in an expression entry area on the calculator; displaying results in a first window on the calculator, wherein the results displayed in the first window comprise a result for the first mathematical expression; displaying, in a second window on the calculator, a usage history comprising the first mathematical expression, a second mathematical expression, and results displayed in the second window, wherein the results displayed in the second window comprise the result for the first mathematical expression and a result for the second mathematical expression, wherein the usage history is displayed in a hierarchical tree such that a result for a given mathematical expression is displayed in the second window on a different hierarchical level than the given mathematical expression; and displaying organizational tabs for the second window, wherein each organizational tab is operable to display a given category of data associated with the usage history, and wherein the results in the first window and the results in the second window are displayed simultaneously.