Question

已知等比數列{a_n}中,a₃=3,a₁₀=384,則該數列的通項a_n=_____________.

Answer 1

解析:a₃=a₁q²=3,a₁₀=a₁q⁹=384,兩式相除得q⁷=128,∴q=2.∴a₁=.

∴a_n=×2^n-1=3×2^n-3.

答案:3×2^n-3