## Tip 75. Compromise of form and content of Mathcad-document

### Fig. 75. Nautilus II

This tip is formed in development of the theme that has been begun in the previous tip, where we have solved the problem about the size of the submarine “Nautilus” of captain Nemo. Another two obtained solutions of this problem is shown in the fig. 75. At that the equations are simplified in the first solution but in the second solution on the contrary they are à complicated. These operations do not have an influence[1] on the results of solution. However they can have an influence on understanding the main sense of the problem by user. “Some simplicity (simplification) is worse than stealing!” – this way we could call this tip as since the main point of it concludes in the following. It is not worth to simplify the formulas in Mathcad-document in the hope of “help” a computer to solve a problem. On the contrary it is worth to complicate the formulas for help a man to understand the main point of the problem and features of its solution. To simplify a formula (see the area with the name “Simplification of formula” in the fig. 75) it is possible with help of the command Simplify from menu Symbolic with following handmade revision. To complicate the problem (see the area “Complication of formula” at fig. 75) it is possible by three methods:

§         formulas are “hanged round” with commentaries: textual embedding (the equation for the area of the submarine) or textual constants (the equation for volume of the submarine);

§         the sum in the equation for the area of the submarine is written not as a line but as a column (for it we use the chord Ctrl+Enter, which inserts break of a page in “clear field but in formula this chord is the operator of addition in column);

Under the word Given there are two equations that explain a main point of the problem (geometry of the rostrum and stern of the submarine), that are turned off from the calculations[2] (see the square in the right upper corner of the formulas) and that have become the commentaries. Turning off the operator from the calculation is good commentary (it is impossible to input mathematical operators in a text).

[1] Here it is possible to speak not about  qualitative, but about quantitative directions of the given numerical solution: about speed of search the reply and about its accuracy.

[2] Disconnection of the operator is done with help of the command Disable Evaluation in contextual menu pulldown by click on right key of a mouse.