Q. Find the 10th term of the geometric sequence 1,−2,4,…Answer:
Identify Sequence Type: Identify the type of sequence. The given sequence alternates signs and each term is twice the absolute value of the previous term, which indicates it is a geometric sequence.
Determine Common Ratio: Determine the common ratio r of the sequence.To find the common ratio, divide the second term by the first term.r=1−2=−2
Use Geometric Sequence Formula: Use the formula for the nth term of a geometric sequence.The nth term Tn of a geometric sequence can be found using the formula Tn=a⋅r(n−1), where a is the first term and n is the term number.
Calculate 10th Term: Calculate the 10th term using the formula.T10=1×(−2)10−1T10=1×(−2)9T10=1×(−512)T10=−512