Q. Find the 11th term of the geometric sequence 7,−21,63,…Answer:
Identify common ratio: Identify the common ratio r of the geometric sequence.To find the common ratio, divide the second term by the first term.r=(−21)/7=−3
Use formula for nth term: Use the formula for the nth term of a geometric sequence.The nth term an of a geometric sequence can be found using the formula an=a1×r(n−1), where a1 is the first term and r is the common ratio.
Substitute values for 11th term: Substitute the values into the formula to find the 11th term. a11=7×(−3)11−1a11=7×(−3)10
Calculate 11th term: Calculate the 11th term.a11=7×(59049) // (−3)10=59049a11=413343
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