Toán Lớp 5: 1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/1256

TRẢ LỜI

1. Gọi tích đó là A

   Ax2=1+1/2+1/4+1/8+1/16+1/32+1/64

   Ax2-A=1+1/2+1/4+1/8+1/16+1/32+1/64-1/2+1/4+1/8+1/16+1/32+1/64+1/128

   A=1-1/128+1/1256

   A=127/128+1/1256

   A = 1247,1875/1256

    

   Trả lời
2. Gọi tích đó là A

   Ax2=1+1/2+1/4+1/8+1/16+1/32+1/64

   Ax2-A=1+1/2+1/4+1/8+1/16+1/32+1/64-1/2+1/4+1/8+1/16+1/32+1/64+1/128

   A=1-1/128+1/1256

   A=127/128+1/1256

   Còn bao nhiêu bn tính nốt

   Trả lời