求值:(1+1⼀2^2)(1-1⼀3^2)……(1-1⼀9^2)(1-1⼀10^2)

求值:(1+1/2^2)(1-1/3^2)……(1-1/9^2)(1-1/10^2)
2024-12-24 18:31:34
推荐回答(2个)
回答1:

(1-1/2^2)(1-1/3^2)……(1-1/9^2)(1-1/10^2)
=(1-1/2)(1+1/2)(1-1/3)(1+1/3)...(1-1/9)(1+1/9)(1-1/10)(1+1/10)
=1/2×3/2×2/3×4/3×...×8/9×10/9×9/10×11/10
=1/2×11/10
=11/20

回答2:

(1+1/2^2)(1-1/3^2)……(1-1/9^2)(1-1/10^2)
=(1+1/2^2)(1-1/3)(1+1/3)(1-1/4)(1+1/4)……(1-1/9)(1+1/9)(1-1/10)(1+1/10)
=(1+1/2^2)(1-1/3)(1+1/10)
=(5/4)*(2/3)*(11/10)
=11/12