(-inf,2/3) or (2/3,inf)
if x=2/3 then y is undefined
Answer: 
Step-by-step explanation:
The given sequence : 2.5,7.5,22.5,67.5,202.5
here first term (a)= 2.5
Second term = 7.5
Third term = 22.5 and so on
The difference between the two consecutive terms is increasing but have common ratio as:
Common ratio (r) = 
So this sequence follows geometric progression.
nth term in GP = 
Required function notation: 
i.e. the function notation of given sequence : 




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