Q. Find the 12th term of the geometric sequence shown below.4x,−8x3,16x5,…Answer:
Identify common ratio and formula: To find the 12th term of a geometric sequence, we need to identify the common ratio (r) and use the formula for the nth term of a geometric sequence, which is an=a1⋅r(n−1), where a1 is the first term and n is the term number.
Find first term: The first term a1 of the sequence is 4x.
Calculate common ratio: To find the common ratio r, we divide the second term by the first term: r=4x−8x3=−2x2.
Find 12th term formula: Now that we have the common ratio, we can find the 12th term a12 using the formula: a12=a1⋅r(12−1)=4x⋅(−2x2)11.
Calculate exponent: We calculate the exponent: (−2x2)11=(−2)11×(x2)11=−2048x22.
Multiply for 12th term: Now we multiply the first term by the result of the exponent calculation to get the 12th term: a12=4x×−2048x22=−8192x23.
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