An arithmetic sequence has the general term u_n = -10n + 10. Calculate u_n when n = 18. u_n =
Answer (1)
To find the value of the general term u n in an arithmetic sequence when n = 18 , we use the given formula for the general term:
u n = − 10 n + 10
Here, n represents the term number in the sequence. Since we are asked to find u n for n = 18 , we substitute 18 into the formula:
u 18 = − 10 × 18 + 10
Now, let's perform the calculations step-by-step:
First, multiply − 10 by 18 : − 10 × 18 = − 180
Next, add 10 to − 180 : − 180 + 10 = − 170
Therefore, the 18th term of the arithmetic sequence is u 18 = − 170 .
This means that when n = 18 , the value of u n is − 170 .
