# Equal

lhs==rhs

returns True if lhs and rhs are identical.

# Details

• lhs==rhs is used to represent a symbolic equation, to be manipulated using functions like Solve.
• lhs==rhs returns True if lhs and rhs are ordinary identical expressions.
• lhs==rhs returns False if lhs and rhs are determined to be unequal by comparisons between numbers or other raw data, such as strings.
• Approximate numbers with machine precision or higher are considered equal if they differ in at most their last seven binary digits (roughly their last two decimal digits).
• For numbers below machine precision, the required tolerance is reduced in proportion to the precision of the numbers.
• 2==2. gives True.
• e1==e2==e3 gives True if all the ei are equal.
• Equal[e] gives True.
• For exact numeric quantities, Equal internally uses numerical approximations to establish inequality. This process can be affected by the setting of the global variable \$MaxExtraPrecision.
• Equal remains unevaluated when lhs or rhs contains objects such as Indeterminate and Overflow.
• In StandardForm and InputForm, lhs==rhs can be input as lhs\[Equal]rhs or lhsrhs.
• It can also be input as \[LongEqual] or lhsrhs.
• In TraditionalForm, lhs==rhs is output as lhsrhs.

# Examples

open allclose all

## Basic Examples(2)

Test equality:

 In[1]:=
 Out[1]=

Represent an equation:

 In[1]:=
 Out[1]=
 In[2]:=
 Out[2]=