If (a_n=n!+n), what will be the value of (a_5)?
Answer and explanation
Correct answer: 125
Given (a_n=n!+n), substitute (n=5): (a_5=5!+5=120+5=125). Therefore, 125 is the correct option. 120 is only the value of (5!), but the additional 5 must also be added. Exam tip: in expressions involving factorials, evaluate the factorial first and then perform the remaining operations.
Frequently asked questions
What is the correct answer to this question?
125
Why is this the correct answer?
Given (a_n=n!+n), substitute (n=5): (a_5=5!+5=120+5=125). Therefore, 125 is the correct option. 120 is only the value of (5!), but the additional 5 must also be added. Exam tip: in expressions involving factorials, evaluate the factorial first and then perform the remaining operations.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: Sequences.
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