<span> To get an explicit formula, we need to find an expression which gives the n-th term without having to compute earlier terms in the sequence. Looking at the numbers, and from the recursive formula, we see that the sequence is built by subtracting n from the previous term. This is similar to the triangular number sequence 1,3,6,10,15,... which has the explicit formula a_n = n(n+1)/2. In our case we are subtracting n from the previous term, so we multiply by -1/2 instead of 1/2. However, we also need to add a constant term to reproduce the numbers of the sequence. We can write a_1 = -1(2)/2 + c = 8. Therefore, c = 9.
So the explict formula is:
a_n = -n(n+1)/2 + 9</span>
Answer: All real numbers except 3
Answer:
B
Step-by-step explanation:
Answer:
y=-7
Step-by-step explanation:
Multiply -3 times 2 1/3
Hope this helps!
define the 3 numbers
smallest number = x
middle number = x + 2
largest number = x + 4
write the equation
sum of the smallest number and twice the middle number
20 more than the largest number
equal the expressions
the numbers should be 10, 12 and 14