Q. Find the 12th term of the geometric sequence shown below.−8x2,16x5,−32x8,…Answer:
Identify Common Ratio: To find the 12th term of a geometric sequence, we need to identify the common ratio (r) of the sequence. The common ratio is found by dividing any term by the previous term.
Calculate Common Ratio: Let's find the common ratio by dividing the second term by the first term: r=−8x216x5=−2x3
Use Formula for nth Term: Now that we have the common ratio, we can 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 12th Term: We want to find the 12th term a12. We already know the first term a1 is −8x2 and the common ratio r is −2x3. Plugging these values into the formula gives us:a12=a1⋅r12−1=−8x2⋅(−2x3)11
Calculate Exponent: Now we need to calculate (−2x3)11. When raising a power to a power, we multiply the exponents: (−2x3)11=(−2)11×(x3)11=−2048x33
Multiply to Find 12th Term: Finally, we multiply the first term by this value to find the 12th term: a12=−8x2×−2048x33=16384x35
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