Question

tính F=\(\left(\frac{7}{2^9}-\frac{14}{2^{11}}+\frac{21}{768}\right)^2\)\(:\left(\frac{5}{2^9}-\frac{20}{2^{12}}+\frac{25}{1280}\right)^2\)

Answer 1

\(F=\left(\dfrac{A}{B}\right)^2\)

\(A=\left(\dfrac{7}{2^9}-\dfrac{14}{2^{11}}+\dfrac{21}{768}\right)=\left(\dfrac{7}{2^9}-\dfrac{14}{2^{11}}+\dfrac{7}{256}\right)=\left(\dfrac{7}{2^9}-\dfrac{7}{2^{10}}+\dfrac{7}{2^8}\right)=7.\left(\dfrac{1}{2^9}-\dfrac{1}{2^{10}}+\dfrac{1}{2^8}\right)\)

\(B=\left(\dfrac{5}{2^9}-\dfrac{20}{2^{12}}+\dfrac{25}{1280}\right)=\left(\dfrac{5}{2^9}-\dfrac{4.5}{2^{12}}+\dfrac{5}{256}\right)=\left(\dfrac{5}{2^9}-\dfrac{5}{2^{10}}+\dfrac{5}{2^8}\right)=5.\left(\dfrac{1}{2^9}-\dfrac{1}{2^{10}}+\dfrac{1}{2^8}\right)\)\(F=\left(\dfrac{A}{B}\right)^2=\left(\dfrac{7}{5}\right)^2\)