( x+ 1/2) + (x+1/4)+(x+1/8)+(x+1/16)=1
Tính: 1/x-1-1/x+1-2/x^2+1-4/x^4+1-8/x^8+1-16/x^16+1
Thực hiện phép trừ:
1/1-x+1/1+x+2/1+x^2+4/1+x^4+8/1+x^8+16/1+x^16
\(=\dfrac{1+x+1-x}{1-x^2}+\dfrac{2}{1+x^2}+...+\dfrac{16}{1+x^{16}}\)
\(=\dfrac{2}{1-x^2}+\dfrac{2}{1+x^2}+...+\dfrac{16}{1+x^{16}}\)
\(=\dfrac{2+2x^2+2-2x^2}{1-x^4}+...+\dfrac{16}{1+x^{16}}\)
\(=\dfrac{4}{1-x^4}+\dfrac{4}{1+x^4}+\dfrac{8}{1+x^8}+...+\dfrac{16}{1+x^{16}}\)
\(=\dfrac{4+4x^4+4-4x^4}{1-x^8}+\dfrac{8}{1+x^8}+\dfrac{16}{1+x^{16}}\)
\(=\dfrac{8+8x^8+8-8x^8}{1-x^{16}}+\dfrac{16}{1+x^{16}}\)
\(=\dfrac{16+16x^{16}+16-16x^{16}}{1-x^{32}}=\dfrac{32}{1-x^{32}}\)
thực hiện phép tính 1/x-1-1/x+1-2/x^2+1-4/x^4+1-8/x^8+1-16/x^16+1
*) tính tổng
A= 1/x-1 - 1/x+1 - 2/x^2+1 - 4/x^4+1 - 8/x^8+1 - 16/x^16+1
-) 1 phần x-1 trừ đi 1 phần x mũ 2 +1 trừ đi 4 phần x mũ 4 +1 trừ đi 8 phần x mũ 8 + 1 trừ đi 16 phần x mũ 16 +1 ( giải thích cho các ban hiểu ấy mà)
1/1-x +1/1+x +2/1+x^2 +4/1+x^4 +8/1+x^8 +16/1+x^16 = 32/1-x^32 c/m
\(\dfrac{1}{1-x}+\dfrac{1}{1+x}+\dfrac{2}{1+x^2}+\dfrac{4}{1+x^4}+\dfrac{8}{1+x^8}+\dfrac{16}{1+x^{16}}\)
\(=\dfrac{1+x+1-x}{1-x^2}+\dfrac{2}{1+x^2}+\dfrac{4}{1+x^4}+\dfrac{8}{1+x^8}+\dfrac{16}{1+x^{16}}\)
\(=\dfrac{2+2x^2+2-2x^2}{1-x^4}+\dfrac{4}{1+x^4}+\dfrac{8}{1+x^8}+\dfrac{16}{1+x^{16}}\)
\(=\dfrac{4+4x^4+4-4x^4}{1-x^8}+\dfrac{8}{1+x^8}+\dfrac{16}{1+x^{16}}\)
\(=\dfrac{8+8x^8+8-8x^8}{1-x^{16}}+\dfrac{16}{1+x^{16}}\)
\(=\dfrac{16+16x^{16}+16-16x^{16}}{1-x^{32}}=\dfrac{32}{1-x^{32}}\)
(x^2+x+1)(x^4+x^2+1)(x^8+x^4+1)(x^16+x^8+1)(x^32+x^16+1) rút gọn zùm mình với
https://www.youtube.com/watch?v=cFZDEMTQQCs
Đề Phân tích đa thức thành nhân tử 1/(1 - x )+ 1/(1+x)+2/(1+x^2)+ 4/(1+x^4)+8/(1+x^8) - 16/(1+ x^16)
viết gọn biểu thức :
(x^2-x+1)(x^4-x^2+1)(x^8-x^4+1)(x^16-x^8+1)(x^32-x^16+1)
\(\frac{1}{1-x}+\frac{1}{1+x}+\frac{2}{1+x^2}+\frac{4}{1+x^4}+\frac{8}{1+x^8}+\frac{16}{1+x^{16}}\)
Thu gọn : \(\frac{1}{1-x}+\frac{1}{1+x}+\frac{2}{1+x^2}+\frac{4}{1+x^4}+\frac{8}{1+x^8}+\frac{16}{1+x^{16}}\)
\(bt=\frac{1\left(1+x\right)}{\left(1-x\right)\left(1+x\right)}+\frac{1\left(1-x\right)}{\left(1+x\right)\left(1-x\right)}+\frac{2}{1+x^2}+\frac{4}{1+x^4}+\frac{8}{1+x^8}+\frac{16}{1+x^{16}}\)
\(=\frac{2}{1-x^2}+\frac{2}{1+x^2}+\frac{4}{1+x^4}+\frac{8}{1+x^8}+\frac{16}{1+x^{16}}\)
\(=\frac{2\left(1+x^2\right)}{\left(1-x^2\right)\left(1+x^2\right)}+\frac{2\left(1-x^2\right)}{\left(1+x^2\right)\left(1-x^2\right)}+\frac{4}{1+x^4}+\frac{8}{1+x^8}+\frac{16}{1+x^{16}}\)
\(=\frac{4}{1-x^4}+\frac{4}{1+x^4}+\frac{8}{1+x^8}+\frac{16}{1+x^{16}}\)
\(=\frac{8}{1-x^8}+\frac{8}{1+x^8}+\frac{16}{1+x^{16}}\)
\(=\frac{16}{1-x^{16}}+\frac{16}{1+x^{16}}\)
\(=\frac{32}{1-x^{32}}\)
Chúc bạn làm bài tốt