Tính nhanh 4.(3²+1)(3^4+1)(3^8+1)(3^16+1)-1 04/09/2021 Bởi Quinn Tính nhanh 4.(3²+1)(3^4+1)(3^8+1)(3^16+1)-1
`4.(3^2+1)(3^4+1)(3^8+1)(3^{16}+1)-1` `=1/2. 2.(3+1)(3^2+1)(3^4+1)(3^8+1)(3^{16}+1)-1` `=1/2. (3-1)(3+1)(3^2+1)(3^4+1)(3^8+1)(3^{16}+1)-1` `=1/2 .(3^2-1)(3^2+1)(3^4+1)(3^8+1)(3^{16}+1)-1` `=1/2 .(3^4-1)(3^4+1)(3^8+1)(3^{16}+1)-1` `=1/2 .(3^8-1)(3^8+1)(3^{16}+1)-1` `=1/2 .(3^{16}-1)(3^{16}+1)-1` `=1/2 .(3^{32}-1)+1` `=1/2 . 3^{32} – 1/2+1` `=1/2 . 3^{32} + 1/2` `= \frac{3^{32}+1}{2}.` Bình luận
`4.(3^2+1)(3^4+1)(3^8+1)(3^{16}+1)-1`
`=1/2. 2.(3+1)(3^2+1)(3^4+1)(3^8+1)(3^{16}+1)-1`
`=1/2. (3-1)(3+1)(3^2+1)(3^4+1)(3^8+1)(3^{16}+1)-1`
`=1/2 .(3^2-1)(3^2+1)(3^4+1)(3^8+1)(3^{16}+1)-1`
`=1/2 .(3^4-1)(3^4+1)(3^8+1)(3^{16}+1)-1`
`=1/2 .(3^8-1)(3^8+1)(3^{16}+1)-1`
`=1/2 .(3^{16}-1)(3^{16}+1)-1`
`=1/2 .(3^{32}-1)+1`
`=1/2 . 3^{32} – 1/2+1`
`=1/2 . 3^{32} + 1/2`
`= \frac{3^{32}+1}{2}.`
😀