Câu hỏi của Trần Hà My

Question

Tính nhanh:1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256 + 1/512

SKT_Rengar Thợ Săn Bóng... · Accepted Answer

1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256 + 1/512A x 2 = 1/4 ( 1/4 + 1/8 + 1/16 + .......... + 1/512 ) - 1/512A x 2 = 1/4 - A - 1/512A x 2 - A = 1/4 - 1/512A = 1/4 - 1/512A = 127/512Câu trả lời: 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256 + 1/512A x 2 = 1/4 ( 1/4 + 1/8 + 1/16 + .......... + 1/512 ) - 1/512A x 2 = 1/4 - A - 1/512A x 2 - A = 1/4 - 1/512A = 1/4 - 1/512A = 127/512