9.3.4  Left side of an equation

(See Section 5.2.4, Section 8.2.3, Section 6.5.1, Section 6.6.2, Section 6.3.6, Section 9.3.5, Section 28.2.8 and Section 28.2.9 for other uses of left.)

The left or lhs command finds the left hand side of an equation.

• left takes lhs=rhs, an equation.
• left(lhs=rhs) returns lhs.

Example