Documentation

This is machine translation

Translated by Microsoft
Mouseover text to see original. Click the button below to return to the English verison of the page.

Note: This page has been translated by MathWorks. Please click here
To view all translated materals including this page, select Japan from the country navigator on the bottom of this page.

solvelib::preImage

Preimage of a set under a mapping

MuPAD® notebooks are not recommended. Use MATLAB® live scripts instead.

MATLAB live scripts support most MuPAD functionality, though there are some differences. For more information, see Convert MuPAD Notebooks to MATLAB Live Scripts.

Syntax

solvelib::preImage(a, x, S)

Description

solvelib::preImage(a, x, S) returns the set of all numbers y such that substituting y for x in a gives an element of S.

S can be a set of any type (finite or infinite).

Examples

Example 1

In case of a finite set S, the preimage of S is just the union of all sets solve(a=s, x), where s ranges over the elements of S.

solvelib::preImage(x^2+2, x, {11, 15});

Note that computing this set may take a long time for large finite sets:

time(solvelib::preImage(x, x, 
           Z_ intersect Dom::Interval(0, 1000000)))

Example 2

For intervals, the preimage is usually an interval or a union of intervals.

solvelib::preImage(x^2+2, x, Dom::Interval(3..7));

Parameters

a

Arithmetic expression

x

Identifier

S

Set

Return Values

Set

See Also

MuPAD Functions

Was this topic helpful?