Ta có : 55⁶⁶ = [(11.5)⁶]¹¹ = (11⁶ . 5⁶)¹¹ = (11⁵ . 11 . 5⁶)¹¹

66⁵⁵ = [(11.6)⁵]¹¹ = (11⁵ . 6⁵)¹¹

Vì 11 . 5⁶ > 6⁵ nên 55⁶⁶ > 66⁵⁵

55 mũ 66 < 66 mũ 55

55⁶⁶ >  66⁵⁵

mk gthik chắc bn k hiểu nên tốt nhất mk k gthik 

Ta có: 55^66 = (55^66)^11 =  ((11.5)^6)^11 = (11^6.5^6)^11 = (11^5.11.5^6)^11

           66^55 = (66^5)^11 = ((11.6)^5^11 = (11^5.6^5)^11

Vì 11.5^6 > 6^5 nên 55^66 > 66^55

Nếu đúng cho mk một like nha !

55⁶⁶>66⁵⁵

55⁶⁶>66⁵⁵. like ik ha.^-^

Ta có:    55^66 = (55^6)^11 = ((11.5)^6)^11 = (11^6.5^6)^11 = (11^5.11.5^6)^11

              66^55 = (66^5)^11 = ((11.6)^5)^11 = (11^5.6^5)^11

Vì 11.5^6 > 6^5 nên 55^66 > 66^55

66⁵⁵ > 55⁶⁶

=\(55^{6x11}và66^{5x11}\)

=\(330^{11}va330^{11}\)

=>\(55^{66}=66^{55}\)

do những số đó bé hơn 1 nên cộng lại vẫn bé hơn 1

  A =  \(\dfrac{1}{3}\) +    \(\dfrac{1}{6}\) +  \(\dfrac{1}{10}\)  + \(\dfrac{1}{15}\) + ..+ \(\dfrac{1}{55}\)+ \(\dfrac{1}{66}\)

A  = 2  \(\times\) ( \(\dfrac{1}{6}\) + \(\dfrac{1}{12}\)  + \(\dfrac{1}{20}\) + \(\dfrac{1}{30}\) +...+ \(\dfrac{1}{110}\) + \(\dfrac{1}{132}\))

A  = 2 \(\times\) ( \(\dfrac{1}{2.3}\) + \(\dfrac{1}{3.4}\) +  \(\dfrac{1}{4.5}\)+ \(\dfrac{1}{5.6}\) +...+ \(\dfrac{1}{10.11}\)+ \(\dfrac{1}{11.12}\))

A = 2 \(\times\) ( \(\dfrac{1}{2}\) - \(\dfrac{1}{3}\) + \(\dfrac{1}{3}\) - \(\dfrac{1}{4}\) + \(\dfrac{1}{4}\) - \(\dfrac{1}{5}\) + \(\dfrac{1}{5}\) - \(\dfrac{1}{6}\) +...+ \(\dfrac{1}{10}\) - \(\dfrac{1}{11}\)+ \(\dfrac{1}{11}\) - \(\dfrac{1}{12}\))

A = 2 \(\times\) ( \(\dfrac{1}{2}\) - \(\dfrac{1}{12}\))

A = 1 - \(\dfrac{1}{6}\) < 1

Vậy A = \(\dfrac{1}{3}\) + \(\dfrac{1}{6}\) + \(\dfrac{1}{10}\) + \(\dfrac{1}{15}\) + ...+ \(\dfrac{1}{55}\)+ \(\dfrac{1}{66}\) < 1