Question

what do this symbol mean ??​

Answer 1

This symbol means " belongs to" .

It is a Greek letter and read as "belongs to" .

( Reading your question only , it says - (a,b,c BELONGS TO R )

For instance, 'Let a∈A' means 'Let a be an element of A'

∈ (mathematics) means that it is an element in the set of… For eg...x ∈ ℕ denotes that x is within the set of natural numbers.

The relation "is an element of", also called set membership, is denoted by the symbol "∈". Writing {\displaystyle x\in A} x\in A means that "x is an element of A". Equivalent expressions are "x is a member of A", "x belongs to A", "x is in A" and "x lies in A". The expressions "A includes x" and "A contains x" are also used to mean set membership, however some authors use them to mean instead "x is a subset of A"..

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