Q. Find the 8th term of the geometric sequence 9,−18,36,…Answer:
Find Common Ratio: To find the 8th term of the geometric sequence, we first need to determine the common ratio (r) of the sequence. The common ratio is found by dividing any term by the previous term.Calculation: r=(−18)/9=−2
Calculate 8th Term: Now that we have the common ratio, we can find the nth term of a geometric sequence using the formula: an=a1⋅r(n−1), where an is the nth term, a1 is the first term, and r is the common ratio.Calculation: a8=9⋅(−2)8−1
Simplify Exponent: We simplify the exponent part of the formula: (−2)(8−1)=(−2)7.Calculation: (−2)7=−128
Multiply First Term: Now we multiply the first term by the result from the previous step to find the 8th term.Calculation: a8=9×(−128)=−1152