If (a_n=2^n+1), what is the third term?
Answer and explanation
Correct answer: 9
For the third term, substitute n=3: a_3=2^3+1=8+1=9. Therefore, 9 is correct. Option 8 is only the value of 2^3; the +1 in the formula still has to be added. Exam tip: when finding an nth term, substitute the value of n first, then evaluate powers and other operations in order.
Frequently asked questions
What is the correct answer to this question?
9
Why is this the correct answer?
For the third term, substitute n=3: a_3=2^3+1=8+1=9. Therefore, 9 is correct. Option 8 is only the value of 2^3; the +1 in the formula still has to be added. Exam tip: when finding an nth term, substitute the value of n first, then evaluate powers and other operations in order.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: nth term.
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