(1+1/3)(1+1/3^2)(1+1/3^4)(1+1/3^8)
=(1-1/3)(1+1/3)(1+1/3^2)(1+1/3^4)(1+1/3^8)÷2/3
=(1-1/3^2)(1+1/3^2)(1+1/3^4)(1+1/3^8)×3/2
=(1-1/3^4)(1+1/3^4)(1+1/3^8)×3/2
=(1-1/3^8)(1+1/3^8)×3/2
=(1-1/3^16)×3/2
=3/2-1/(2×3^15)
(1+1/3)(1+1/3^2)(1+1/3^4)(1+1/3^8)
=(1-1/3)(1+1/3)(1+1/3^2)(1+1/3^4)(1+1/3^8)÷2/3
=(1-1/3^2)(1+1/3^2)(1+1/3^4)(1+1/3^8)×3/2
=(1-1/3^4)(1+1/3^4)(1+1/3^8)×3/2
=(1-1/3^8)(1+1/3^8)×3/2
=(1-1/3^16)×3/2
=3/2-1/(2×3^15)