Algebraic Thinking

Ok....look at this....the first term [ n = 1 ] is just:

 (-1)^1 * (1/2)^(1 - 1) = -1 * (1/2)^0   = -1 * 1 = -1

And the third term is just:

(-1)^3 * (1/2)^(3 -1)  = -1 * (1/2)^2 = -1 * (1/4) = -1/4

So...the 4th term  is  just:

(-1)^4 * (1/2)^(4 - 1)   =  1 * (1/2)^3 =   1 * (1/8)   = 1/8

Does that help???

The nth term of the sequence is given by: (-1)^n * (1/2)^(n - 1)

So....the 4th term is given by :    (1/2)(4-1) = (-1)^4 * (1/2)^3   =  1/8

still confused....