Multiple choice

Find the seventh term of the geometric sequence $1, -3, 9, -27, ....$

  1. -243

  2. -30

  3. 81

  4. 189

  5. 729
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E Correct answer
Explanation

This is a geometric sequence with first term a=1 and common ratio r=-3. The nth term is a*r^(n-1). The 7th term is 1*(-3)^6 = 729.

AI explanation

This is a geometric sequence with a first term of 1 and a common ratio of -3. Using the explicit formula for a geometric sequence, a_n = a * r^(n-1), we calculate the seventh term by substituting n = 7 to get 1 * (-3)^(7-1). Since (-3)^6 equals 729, the seventh term is 729.

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