Question 1028777
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What is the arithmetic mean an of the given terms 
An-1=4,an+1=12
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According to <A HREF=https://en.wikipedia.org/wiki/Arithmetic_mean>this article</A> of Wikipedia


   In mathematics and statistics, the arithmetic mean, or simply the mean or average when the context is clear, 
   is the sum of a collection of numbers divided by the number of numbers in the collection.


Based on this, the arithmetic mean in your case is {{{(4+12)/2}}} = {{{16/2}}} = 8.
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