Question

In an arithmetic sequence, a1=5 and a6=-5. Determine an equation for an, the nth term of this sequence.

Answer 1

Answer: 7 - 2n

Explanation:

a1 = 5

a6 = -5 = a + (n - 1)d = a + (6 - 1)d

a + 5d = -5

Since a1 = 5

5 + 5d = -5

5d = -5 - 5

5d = -10

d = -10/5

d = -2

Therefore, the equation to calculate the nth term of this sequence will be:

= a + (n-1)d

= a + (n - 1)-2

= 5 -2n +2

= 7 - 2n