rhs

Right side (RHS) of equation

Syntax

rhsEqn = rhs(eqn)

Description

rhsEqn = rhs(eqn) returns the right side of the symbolic equation eqn. The value of eqn also can be a symbolic condition, such as x > 0. If eqn is an array, then rhs returns an array of the right sides of the equations in eqn.

Conditions that use the > or >= operator are internally rewritten using the < or <= operator. Therefore, rhs returns the original left side. For example, rhs(x > 0) returns x.

Examples

Find Right Side of Equation

Find the right side of the equation $2\mathit{y}={\mathit{x}}^2$ by using rhs.

First, declare the equation.

syms x y
eqn = 2*y == x^2

eqn = $$2\hspace{0.17em}y=x^2$$

Find the right side of eqn by using rhs.

rhsEqn = rhs(eqn)

rhsEqn = $$x^2$$

Find Right Side of Condition

Find the right side of the condition $\mathit{x}<\mathit{y}+1$ by using rhs.

First, declare the condition.

syms x y
cond = x < y + 1

cond = $$x<y+1$$

Find the right side of cond by using rhs.

rhsCond = rhs(cond)

rhsCond = $$y+1$$

Find Right Side of Equations in Array

For an array that contains equations and conditions, rhs returns an array of the right sides of those equations or conditions. The output array is the same size as the input array.

Find the right side of the equations and conditions in the vector V.

syms x y
V = [y^2 == x^2, x ~= 0, x*y >= 1]

V = $$\left(\begin{array}{ccc}{y}^2=x^2& x\ne 0& 1\le x\hspace{0.17em}y\end{array}\right)$$

rhsV = rhs(V)

rhsV = $$\left(\begin{array}{ccc}{x}^2& 0& x\hspace{0.17em}y\end{array}\right)$$

Because any condition using the >= operator is internally rewritten using the <= operator, the sides of the last condition in V are exchanged.

Find Right Side of Equation Involving Symbolic Matrix Variables

Find the right side of a symbolic equation that involves symbolic matrix variables.

Create the symbolic matrix variables and the symbolic equation.

syms A [2 2] matrix
syms B [2 1] matrix
syms C [1 2] matrix
eqn = B*C == A*A - 2*A + eye(2)

eqn = $$B\hspace{0.17em}C={\mathrm{I}}_2-2\hspace{0.17em}A+A^2$$

Find the right side of the equation by using rhs.

rhsEqn = rhs(eqn)

rhsEqn = $${\mathrm{I}}_2-2\hspace{0.17em}A+A^2$$

Input Arguments

eqn — Equation or condition

symbolic equation | symbolic condition | vector of symbolic equations or conditions | matrix of symbolic equations or conditions | multidimensional array of symbolic equations or conditions

Equation or condition, specified as a symbolic equation or condition, or a vector, matrix, or multidimensional array of symbolic equations or conditions.

Data Types: sym | symfun | symmatrix | symfunmatrix

Version History

Introduced in R2017a

R2025a: Get left and right sides of symbolic equation that includes piecewise expressions

You can use the lhs and rhs functions to get the left and right sides of a symbolic equation that includes piecewise expressions. For an example, see Solve System of Equations with Piecewise Expressions.

R2022b: Find right side of symbolic equation or condition involving symbolic matrix variables and matrix functions

The rhs function accepts a symbolic equation or condition involving symbolic matrix variables and matrix functions as an input argument. The input data type can be symmatrix or symfunmatrix. For an example, see Find Right Side of Equation Involving Symbolic Matrix Variables.