lhs

Left side (LHS) of equation

Syntax

lhs(eqn)

Description

lhs(eqn) returns the left 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 lhs returns an array of the left sides of the equations in eqn.

Examples

Find Left Side of Equation

Find the left side of the equation 2*y == x^2 by using lhs.

First, declare the equation.

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

eqn =
2*y == x^2

Find the left side of eqn by using lhs.

lhsEqn = lhs(eqn)

lhsEqn =
2*y

Find Left Side of Condition

Find the left side of the condition x + y < 1 by using lhs.

First, declare the condition.

syms x y
cond = x + y < 1

cond =
 x + y < 1

Find the left side of cond by using lhs.

lhsCond = lhs(cond)

lhsCond =
 x + y

Note

Conditions that use the > operator are internally rewritten using the < operator. Therefore, lhs returns the original right side. For example, lhs(x > a) returns a.

Find Left Side of Equations in Array

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

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

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

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

lhsV = lhs(V)

lhsV =
[ y^2, x, 1]

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

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.

Version History

Introduced in R2017a