Which expression correctly gives the nth term of an arithmetic sequence with first term a1 and common difference d?

Master the Praxis Mathematics (5165) Test. Enhance your skills with flashcards and practice questions, each with detailed explanations. Ace your exam confidently!

Multiple Choice

Which expression correctly gives the nth term of an arithmetic sequence with first term a1 and common difference d?

Explanation:
In an arithmetic sequence, each step adds the same amount d to the previous term. To reach the nth term from the first term a1, you’ve taken n-1 steps, so you add (n-1)d to a1. That gives the nth term as a1 + (n-1)d. For example, with a1 = 5 and d = 3, the sequence goes 5, 8, 11, 14, and the fourth term is 5 + 3(4−1) = 14. The other expressions fail basic checks: a1 + nd would not yield a1 when n = 1; a1 + (n-2)d misplaces the starting term; and a1 + d is a fixed amount, not depending on n.

In an arithmetic sequence, each step adds the same amount d to the previous term. To reach the nth term from the first term a1, you’ve taken n-1 steps, so you add (n-1)d to a1. That gives the nth term as a1 + (n-1)d. For example, with a1 = 5 and d = 3, the sequence goes 5, 8, 11, 14, and the fourth term is 5 + 3(4−1) = 14. The other expressions fail basic checks: a1 + nd would not yield a1 when n = 1; a1 + (n-2)d misplaces the starting term; and a1 + d is a fixed amount, not depending on n.

Subscribe

Get the latest from Examzify

You can unsubscribe at any time. Read our privacy policy