First we need to determine the type of progression in the question.That's geometric progression. Because the pattern from one sequence to the others are about multiplying.
Second, determine the ratio of the progressionr = a₂/a₁
r = a₂ ÷ a₁
r = 1/2 ÷ 2
r = 1/2 × 1/2
r = 1/4
Third, determine the formula to know the recursive rulea₂ = a × 1/4
a₂ = 1/4 × a
Fourth, determine a₁. a₁ is the first term of the progressiona₁ = 2
Final answer:Recursive rule
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a₁ = 2