Find a recursive formula for the sequence: 3, -5, 11, -21
1 answer:
The correct option is the last:
In fact, every term in the sequence is one more than twice the opposite of the previous one:
We start with 3. Twice its opposite is -6. Plus one, we get -5.
We start with -5. Twice its opposite is 10. Plus one, we get 11.
We start with 11. Twice its opposite is -22. Plus one, we get -21.
You might be interested in
The given expression is
This can be simplified as :
=
We know that:
Similarly we also can simplify:
So our expression will look like this:
=
=
=
=
This can also be written as:
So the Answer is Option B