Q. Find the 10th term of the geometric sequence 5,−25,125,…Answer:
Identify type and ratio: Identify the type of sequence and the common ratio.The given sequence is geometric because each term is multiplied by a common ratio to get the next term.To find the common ratio, divide the second term by the first term.Common Ratio r = −25/5=−5
Use nth term formula: 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.We want to find the 10th term a10, so n=10.
Substitute values: Substitute the values into the formula.a10=5×(−5)10−1a10=5×(−5)9
Calculate 10th term: Calculate the 10th term.a10=5×(−5)9a10=5×(−1953125)a10=−9765625