If A1=-1, A2=1, A3=A2-A1, A4=A3-A2 ....An = An-1 - An-2
what is the sum of A1 to A1000=?
a) 0
b) 1
c) 2
d) 3
e) 4
Answer is D.
what is the sum of A1 to A1000=?
a) 0
b) 1
c) 2
d) 3
e) 4
Answer is D.
Might be long but this is how I did:
sequence: -1 1 2 1 -1 -2 | -1 1 2 1 -1 -2 | ..... period of 6
so 1000/6 = 166 and rem 4
sum of each period is 0, so sum = sum of last 4 terms i.e -1 1 2 1 = 3
