Q. Write an explicit formula for an, the nth term of the sequence 25,15,5,…Answer: an=
Identify Arithmetic Sequence: The given sequence is 25,15,5,… which is an arithmetic sequence because the difference between consecutive terms is constant.
Find Common Difference: To find the common difference d, subtract the second term from the first term: d=15−25=−10.
Use Arithmetic Sequence Formula: The first term of the sequence a1 is 25. The nth term of an arithmetic sequence is given by the formula an=a1+(n−1)d.
Substitute Values: Substitute the values of a1 and d into the formula: an=25+(n−1)(−10).
Simplify Formula: Simplify the formula: an=25−10n+10.
Final Explicit Formula: Combine like terms to get the final explicit formula: an=35−10n.
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