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### Operand

In mathematics an operand is the object of a mathematical operation.

##### Explanation

In functional analysis, physics and quantum mechanics, functions and arguments for clarity are often called operators and operands. An operand is the object or quantity that is operated on.

##### Example 1

You write the differential operator with the letter *D* as

, , , ...

etc.

which stands for *"take the derivative of..."*, so you get *Dx* = 1.

##### Example 2

The Laplace operator of a function describes for three dimensions

##### Example 3

The Hamilton operator *H* is used in the Schrödinger equation

##### Example 4

The energy operator *Ê* acts on the wave function *ψ* (*r, t*) and is written as