Ta có

•   A=1+3⁴+3⁸+3¹²

=>3⁴.A=3⁴+3⁸+3¹²+3¹⁶

<=>81.A-A=3¹⁶-1

<=>A=(3¹⁶-1)/80=538084

•B=1+3²+3⁴+3⁶+3⁸+3¹⁰+3¹²+3¹⁴

=>3².B=3²+3⁴+3⁶+3⁸+3¹⁰+3¹²+3¹⁴+3¹⁶

<=>8.B=3¹⁶-1

<=>B=(3¹⁶-1)/8=53808400

Vậy Q=A/B=538084/53808400=1/100=0.01

Sửa lại:

B=5380840

=>Q=1/10

\(Q=\frac{1+3^4+3^8+3^{12}}{\left(1+3^4+3^8+3^{12}\right)+3^2\left(1+3^4+3^8+3^{12}\right)}\)

\(Q=\frac{1+3^4+3^8+3^{12}}{10\left(1+3^4+3^8+3^{12}\right)}=\frac{1}{10}\)

Cj ko rep đc kịp sr nha

mẫu số :

(1+3^4+3^8+3^12)(1+9)=

ds=1/10

\(\frac{1+3^4+3^8+3^{12}}{1+3^2+3^4+3^6+3^8+3^{10}+3^{12}+3^{14}}\)

\(=\frac{1+3^4+3^8+3^{12}}{\left(1+3^4+3^8+3^{12}\right)+\left(3^2+3^6+3^{10}+3^{14}\right)}\)

\(=\frac{1+3^4+3^8+3^{12}}{\left(1+3^4+3^8+3^{12}\right)+3^2\left(1+3^4+3^8+3^{12}\right)}\)

\(=\frac{1+3^4+3^8+3^{12}}{\left(1+3^4+3^8+3^{12}\right)\left(1+3^2\right)}\)

\(=\frac{1}{1+3^2}\)\(=\frac{1}{10}\)

Xem câu hỏi tương tự nha bạn

\(\frac{4^{10}+8^4}{4^5+8^6}=\frac{\left(2^2\right)^{10}+\left(2^3\right)^4}{\left(2^2\right)^5+\left(2^3\right)^6}=\frac{2^{2.10}+2^{3.4}}{2^{2.5}+2^{3.6}}=\)

\(=\frac{2^{20}+2^{12}}{2^{10}+2^{18}}\)

\(\frac{4^{10}+8^4}{4^5+8^6}=\frac{2^{20}+2^{12}}{2^{10}+2^{18}}=\frac{2^{12}.2^8+2^{12}}{2^{10}+2^{10}.2^8}=\frac{2^{12}\left(1+2^8\right)}{2^{10}\left(1+2^8\right)}=\frac{2^{12}}{2^{10}}=2^2=4\)