Question

So sánh các tích sau bằng cách hợp lí

P1=\(\left(-\dfrac{57}{95}\right).\left(-\dfrac{29}{60}\right)\) ; P2= \(\left(-\dfrac{5}{11}\right).\left(-\dfrac{49}{73}\right)\left(-\dfrac{6}{23}\right)\)

P3= \(\dfrac{-4}{11}.\dfrac{-3}{11}.\dfrac{-2}{11}.........\dfrac{3}{11}.\dfrac{4}{11}\)

Answer 1

Xét : \(P1=\left(-\dfrac{57}{95}\right).\left(-\dfrac{29}{60}\right)\ge0\left(1\right)\)(Vì hai số này cùng dấu)

\(P2=\left(-\dfrac{5}{11}\right).\left(-\dfrac{49}{73}\right)\left(-\dfrac{6}{23}\right)\le0\left(2\right)\)(Tích ba số âm thì luôn âm)

\(P3=\dfrac{-4}{11}.\dfrac{-3}{11}.\dfrac{-2}{11}.\dfrac{-1}{11}.\dfrac{0}{11}......\dfrac{3}{11}.\dfrac{4}{11}=0\left(3\right)\)

Từ \(\left(1\right);\left(2\right);\left(3\right)\)

\(\Rightarrow P1< P3< P2\)