hp40g+.book Page 33 Friday, December 9, 2005 1:03 AM
Typing:
XQ(1.414213562)
gives:
| √2 |
| SOLV menu |
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| The SOLV menu contains functions that enable you to |
| solve equations, linear systems, and differential |
| equations. |
DESOLVE | Solve differential equations |
| DESOLVE enables you to solve differential equations. (For |
| linear differential equations having constant coefficients, |
| it is better to use LDEC.) |
| DESOLVE has two arguments: |
| 1. the differential equation where y' is written as d1Y(X) |
| (or the differential equation and the initial conditions |
| separated by AND), |
| 2. the unknown Y(X). |
| The mode must be set to real. |
| Example 1 |
| Solve: |
| y” + y = cos(x) |
| y(0)=c0 y’(0) =c1 |
| Typing: |
| DESOLVE(d1d1Y(X)+Y(X) = COS(X),Y(X)) |
| gives: |
| Y(X) = cC0 ⋅ cos(x) + |
| 2 |
| cC0 and cC1 are integration constants (y(0) = cC0 y’(0) |
| = cC1). |
| You can then assign values to the constants using the |
| SUBST command. |
Computer Algebra System (CAS) |
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