The expression which defines [tex]S_{n}[/tex] is option c which is [tex]S_{n} =3(1-1/2){n}[/tex].
What is geometric progression?
A geometric progression is basically a sequence in which all the terms have a common ratio. It is also known as G.P.
How to find sum of G.P.?
We have been given a sequence as 3/2+3/4+3/8+3/16+.....
If we carefully see the sequence then we will find that this sequence is a Geometric progression because there is a common ratio between all the terms that is 1/2.
Ratio of first and second term=3/4/3/2=1/2
We know that Sum of GP when n<1 is [tex]a(1-r^{n} )/1-r[/tex]
we have to just put the value of =3/2 and r=1/2 in the above formula.
[tex]S_{n}[/tex]=3/2(1-[tex]1/2^{n}[/tex])/1-1/2
=3/2(1-[tex]1/2^{n}[/tex])/1/2
=3*2/2(1-[tex]1/2^{n}[/tex])
=3(1-[tex]1/2^{n}[/tex])
Hence the expression which denotes [tex]S_{n}[/tex] is 3(1-[tex]1/2^{n}[/tex]).
Learn more about geometric progression at https://brainly.com/question/12006112
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