Question

what is the formula for the number of proper subsets​

Answer 1

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Definition :

Let A and B be two sets. If A is a subset of B and A is not equal to B, then A is called a proper subset of B and we can write it as A C B.

Formula :

2n - 1

Example :

If A = { 1,2,5 } and B = { 1,2,3,4,5 } ,then A is a proper subset of B

=> { 1,2,3,4,5 }

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