find the general term of the sequence : -1/4, 1/16, -1/64, 1/256,...
We can rewrite this sequence as: (-1) / 4, (-1)^2 / 4^2, (-1)^3 / 4^3, (-1)^4 /4 ^4, ...
Now we can see the pattern. The numerator is simply unity (1), alternating in sign while the denominator is increasing powers of 4.
The general term is then t_n = (-1)^n / 4^n, i.e. (-1/4)^n
Answer: General term is t_n = (-1/4)^n, n = 1,2,3, ...