Which sequence is modeled by the graph below?

The sequence is basically points (5,1)(4,2)(3,4) and (2,8)

an = one half(16)n − 1

an = 4(2)n − 1

an = 16(−2)n − 1

an = 16(one half)n − 1

Question

Which sequence is modeled by the graph below?

The sequence is basically points (5,1)(4,2)(3,4) and (2,8)

an = one half(16)n − 1

 an = 4(2)n − 1

 an = 16(−2)n − 1

 an = 16(one half)n − 1

anonymous · Answer

All the n-1 are raised though.

anonymous · Answer

@jim_thompson5910 @ganeshie8

anonymous · Answer

If I were to pick an answer I had picked the first one. Would it be right? @jim_thompson5910

anonymous · Answer

Can anyone help me with this problem?

mosaic · Answer

The first point is (5,1).
Put n = 5, and see which one gives you 1 first.

anonymous · Answer

Oh ok

imstuck · Answer

I think I can give you a good start.  By any chance did you forget the coordinate (1, 16)?

imstuck · Answer

You need that coordinate to find the series.  The first term would be a1 of 16.  To find the ratio you have to decide what you do to the second term to get to the first term, but it has to be in the division format.  To get from 8 to 16 you divide the 8 by 1/2.  So your r is 1/2.  The formula for a geometric sequence is this$$a _{n}=a _{1}r ^{n-1}$$Using your info here you fill in as such$$a _{n}=16(\frac{ 1 }{ 2 })^{n-1}$$It's the last choice of the bunch.

imstuck · Answer

And if you graph these you get from left to right that the first term is y = 16 when x = 1.  Just because they gave you the points in that order does not mean anything.  That's why they gave you coordinates; so you could graph them and see what it looks like.|dw:1403560050288:dw|Or something like that (sort of).