If (a_n=3^n+n^2-1), what is the value of (a_3)?
Answer and explanation
Correct answer: 35
Putting n=3, we get a_3=3^3+3^2-1=27+9-1=35. Therefore, the correct answer is 35. A value such as 33 results from an incorrect calculation of the final subtraction; 27+9-1 equals 35. Exam tip: when finding a term from an explicit rule, substitute the given value of n in every occurrence of n, including powers and squares.
Frequently asked questions
What is the correct answer to this question?
35
Why is this the correct answer?
Putting n=3, we get a_3=3^3+3^2-1=27+9-1=35. Therefore, the correct answer is 35. A value such as 33 results from an incorrect calculation of the final subtraction; 27+9-1 equals 35. Exam tip: when finding a term from an explicit rule, substitute the given value of n in every occurrence of n, including powers and squares.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: Explicit or general rule.
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