Question

Which sequence can be defined by the recursive formula f(1) = 4, f (n + 1) = f(n) - 1.25 for n 2 1?

O 1,-0.25,-1.5, -2.75, -4,...
O 1, 2.25, 3.5, 4.75, 6, ...
O 4,2.75, 1.5, 0.25,-1, ...
O 4,5.25, 6.5, 7.75, 8, ...

Answer 1

the third option

4, 2.75, 1.5, 0.25, -1, -2.25, ...

Explanation:

the first value in the sequence is 4.

that eliminates already answer options 1 and 2.

and the values are going down, as we continuously subtract 1.25 from the previous sequence number.

but answer option 4 shows a sequence, where the values go up.

so, only option 3 remains and is correct

4-1.25 = 2.75

2.75-1.25 = 1.5

1.5-1.25 = 0.25

0.25-1.25 = -1

...