-1/4⁸<1/8⁵

\(\left(-\dfrac{1}{4}\right)^8=\left(\dfrac{1}{4}\right)^8=\left(\dfrac{1}{2}\right)^{16}\)

\(\left(\dfrac{1}{8}\right)^5=\left(\dfrac{1}{2}\right)^{15}\)

mà 16>15

nên \(\left(-\dfrac{1}{4}\right)^8>\left(\dfrac{1}{8}\right)^5\)

Các bạn giúp mk nhé mk đang cần gấp ^_^

a: 3/5>-19/5

b: 8/7<8/3

c: 3/4=15/20

2/5=8/20

mà 15>8

nên 3/4>2/5

d: -3/5=-18/30

-4/6=-20/30

mà -18>-20

nên -3/5>-4/6

a: 3/5>-19/5

b: 8/7<8/3

c: 3/4=15/20

2/5=8/20

mà 15>8

nên 3/4>2/5

d: -3/5=-18/30

-4/6=-20/30

mà -18>-20

nên -3/5>-4/6

Ta có: \(C=1+8\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\)

\(=1+\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\)

\(=1+\left(3^4-1\right)\left(3^4+1\right)\left(3^8+1\right)=1+\left(3^8-1\right)\left(3^8+1\right)=1+3^{16}-1=3^{16}\)

Ta có: \(D=\left(3^3\right)^5+\left(3^5\right)^3\)

\(=3^{15}+3^{15}=2\cdot3^{15}<3\cdot3^{15}=3^{16}\)

=>D<C

chỉ em em follow

B > 1

có:1/4+1/5+1/6+1/7+...+1/9≤nhỏ hơn 1/6.6=1

1/10+1/11+...+1/15 nhỏ hơn1/5.5=1

⇒1/4+1/5+...+1/15nhỏ hơn1+1=2(đpcm)

ta có

\(\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{1}{6}+\dfrac{1}{7}< \dfrac{1}{4}.4\)

\(\Rightarrow\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{1}{6}+\dfrac{1}{7}< 1\)

và:

\(\dfrac{1}{8}+\dfrac{1}{9}+\dfrac{1}{10}+\dfrac{1}{11}+\dfrac{1}{12}+\dfrac{1}{13}+\dfrac{1}{14}+\dfrac{1}{15}< \dfrac{1}{8}.8\)

\(\dfrac{1}{8}+\dfrac{1}{9}+\dfrac{1}{10}+\dfrac{1}{11}+\dfrac{1}{12}+\dfrac{1}{13}+\dfrac{1}{14}+\dfrac{1}{15}< 1\)

\(\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{1}{6}+\dfrac{1}{7}+...+\dfrac{1}{15}< 1+1=2\)

$\frac{1}{4}>\frac{1}{9}$ ; $\frac{5}{8}<\frac{8}{5}$

\(\dfrac{1}{4}< \dfrac{1}{9}\)