please help me!!!!

Question

Consider the first five terms of the following sequence 2,6,18,54,162,... If the sequence defines a function, what is a reasonable domain and range of the function?

a. domain: {1, 2, 3, 4, 5,...} ; range: { 2, 6, 18, 54, 162,...}

b . Domain: all real numbers; Range: all real numbers

c. Domain : {1,2,3,4,5,...} ;Range : all real numbers D. Domain: all real numbers; Range: {2,6,18,54,162,...}

Answer 1

If you divide by 2, you get 1,3,9,27,81,... which is 3^n-1

a_n = 2(3)^n-1

So, for 1,2,3,4,5,... a_n = 2,6,19,54,162,...

Looks like (a) is the best fit.

All real numbers would include fractions and negative numbers. We just need positive integers in the domain and range.