# nth term

• Jan 10th 2013, 02:15 PM
tahirakw
nth term
1, 1/2, 1/4, 1/8, 1/16,.....
in the sequence the first term is one and each term after the first is half the proceeding term. which of following answers represents the nth term of this sequence, where n is positive?

its 1/2^n-1 because 1/2^3= 1/8 1/2^2=1/2 ------- but my coworker said its 1/2^n

Can someone explain to me if i am doing this correctly.
• Jan 10th 2013, 02:25 PM
Prove It
Re: nth term
It depends whether or not the first term is considered to be term zero or term one.
• Jan 10th 2013, 02:26 PM
tahirakw
Re: nth term
the first term is 1.
• Jan 10th 2013, 02:58 PM
Plato
Re: nth term
Quote:

Originally Posted by tahirakw
the first term is 1.

You did not understand reply #2, did you?

It depends on where we begin the index.

We could define it as $t_k=2^{-k}$ for $k=0,~1,~2,\cdots$.
OR we could define it as $t_k=2^{-k+1}$ for $k=1,~2,~3,\cdots$.