Q. Find the 11th term of the geometric sequence shown below.−6x8,18x10,−54x12,…Answer:
Identify common ratio: Identify the common ratio (r) of the geometric sequence by dividing the second term by the first term.Calculation: r=−6x818x10=−3x2
Use nth term formula: 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.Calculation: We need to find the 11th term, so n=11.
Substitute values: Substitute the known values into the formula to find the 11th term.Calculation: a11=−6x8⋅(−3x2)(11−1)
Simplify exponent: Simplify the exponent in the formula.Calculation: a11=−6x8⋅(−3x2)10
Calculate power: Calculate the power of −3x2 raised to the 10th power.Calculation: (−3x2)10=(−3)10⋅(x2)10
Simplify powers: Simplify the powers.Calculation: (−3)10=59049 and (x2)10=x20
Multiply by first term: Multiply the simplified powers by the first term to get the 11th term.Calculation: a11=−6x8⋅59049⋅x20
Combine x terms: Combine the x terms by adding the exponents.Calculation: a11=−6⋅59049⋅x8+20
Simplify multiplication: Simplify the multiplication to find the 11th term.Calculation: a11=−6⋅59049⋅x28
Calculate product: Calculate the product of −6 and 59049.Calculation: a11=−354294⋅x28
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