www.delorie.com/gnu/docs/calc/calc_259.html | search |
Buy the book! | |
[ < ] | [ > ] | [ << ] | [ Up ] | [ >> ] | [Top] | [Contents] | [Index] | [ ? ] |
The a S (calc-solve-for
) [solve
] command rearranges
an equation to solve for a specific variable. An equation is an
expression of the form L = R. For example, the command a S x
will rearrange y = 3x + 6 to the form, x = y/3 - 2. If the
input is not an equation, it is treated like an equation of the
form X = 0.
This command also works for inequalities, as in y < 3x + 6. Some inequalities cannot be solved where the analogous equation could be; for example, solving a < b c for b is impossible without knowing the sign of c. In this case, a S will produce the result b != a/c (using the not-equal-to operator) to signify that the direction of the inequality is now unknown. The inequality a <= b c is not even partially solved. See section 7.6 Declarations, for a way to tell Calc that the signs of the variables in a formula are in fact known.
Two useful commands for working with the result of a S are a . (see section 11.10 Logical Operations), which converts x = y/3 - 2 to y/3 - 2, and s l (see section 13.4 The Let Command) which evaluates another formula with x set equal to y/3 - 2.
11.6.1 Multiple Solutions 11.6.2 Solving Systems of Equations 11.6.3 Decomposing Polynomials
webmaster donations bookstore | delorie software privacy |
Copyright © 2003 by The Free Software Foundation | Updated Jun 2003 |