你好!用X表示出现次数P(X=0) = 0.5^5 = 1/32P(X=1) = C(5,1) * 0.5 * 0.5^4 = 5/32P(X=2) = C(5,2) * 0.5² * 0.5³ = 5/16P(X=3) = C(5,3) * 0.5³ * 0.5² = 5/16P(X=4) = C(5,4) * 0.5⁴ * 0.5 = 5/32P(X=5) = 0.5^5 = 1/32至少出现一次的概率P(X ≥ 1) = 1 - P(X=0) = 31/32
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