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BN
1
CC
8 tháng 9 2019
Có : \(\frac{a}{b}=\frac{a\left(b+1\right)}{b\left(b+1\right)}=\frac{ab+a}{b\left(b+1\right)}\)
\(\frac{a+1}{b+1}=\frac{\left(a+1\right)b}{\left(b+1\right)b}=\frac{ab+b}{b\left(b+1\right)}\)
Vì b > 0 => b + 1 > 0 => b(b+1) > 0
+ nếu a > b => ab + a > ab + b => \(\frac{ab+a}{b\left(b+1\right)}>\frac{ab+b}{b\left(b+1\right)}\Rightarrow\frac{a}{b}>\frac{a+1}{b+1}\)
+nếu a < b => ab + a < ab + b => \(\frac{ab+a}{b\left(b+1\right)}< \frac{ab+b}{b\left(b+1\right)}\Rightarrow\frac{a}{b}< \frac{a+1}{b+1}\)
+nếu a = b => \(\frac{a}{b}=\frac{a+1}{b+1}\)
ii
LT
14 tháng 5 2019
1b)
\(VT=\left(sin20-sin100\right)+2sin40\)
\(=\left[2cos60sin\left(-40\right)\right]+2sin40\)
\(=sin40\left(-2cos60+2\right)\)
=\(=sin40\left(dpcm\right)\)
16 tháng 9 2018
chọn gốc tọa độ tại A, chiều dương từ A-B, gốc thời gian lúc 7h
a=20cm/s2=0,2m/s2
v=36km/h=10m/s
x1=x0+v0.t+a.t2.0,5=10t-0,1t2
x2=x0+v0.t+a.t2.0,5=560-0,2t2
hai xe gặp nhau\(\Rightarrow\)x1=x2\(\Rightarrow\)\(\left[{}\begin{matrix}t=-140\left(l\right)\\t=40\left(n\right)\end{matrix}\right.\)
vậy hai xe gặp nhau lúc 7h 40 giây
vị trí hai xe x1=x2=240km
khoảng cách hai xe lúc t=50s
\(\Delta\)x=\(\left|x_1-x_2\right|\)=190km
10 tháng 2 2022
Bài 3:
Gọi số học sinh là x
Theo đề, ta có: \(x-5\in BC\left(8;12;15\right)\)
mà 300<=x<=400
nên x=365
giúp với giúp với giúp e với ạ. e cảm ơn
TD
6 tháng 2 2022
a)\(-1,6:\left(1+\dfrac{2}{3}\right)=-1,6:\dfrac{5}{3}=-\dfrac{8}{5}.\dfrac{3}{5}=\dfrac{-24}{25}\)
b)\(\left(\dfrac{-2}{3}\right)+\dfrac{3}{4}-\left(-\dfrac{1}{6}\right)+\left(\dfrac{-2}{5}\right)=-\dfrac{2}{3}+\dfrac{3}{4}+\dfrac{1}{6}-\dfrac{2}{5}=\dfrac{-40+45+10-24}{60}=\dfrac{-9}{60}=\dfrac{-3}{20}\)
c)\(\left(\dfrac{-3}{7}:\dfrac{2}{11}+\dfrac{-4}{7}:\dfrac{2}{11}\right).\dfrac{7}{33}=\left(\dfrac{-3}{7}.\dfrac{11}{2}+\dfrac{-4}{7}.\dfrac{11}{2}\right).\dfrac{7}{33}=\left[\dfrac{11}{2}\left(\dfrac{-3}{7}+\dfrac{-4}{7}\right)\right].\dfrac{7}{33}=\dfrac{-11}{2}.\dfrac{7}{33}=\dfrac{-7}{6}\)
d)\(\dfrac{-5}{8}+\dfrac{4}{9}:\left(\dfrac{-2}{3}\right)-\dfrac{7}{20}.\left(\dfrac{-5}{14}\right)=\dfrac{-5}{8}-\dfrac{4}{9}.\dfrac{3}{2}+\dfrac{1}{8}=\dfrac{-5}{8}+\dfrac{1}{8}-\dfrac{2}{3}=-\dfrac{7}{6}\)
10 tháng 10 2023
Christmas is a magical and enchanting time of year. It is a joyous and festive occasion filled with love, happiness, and excitement. The air is filled with a warm and cozy atmosphere, as families come together to celebrate. The beautifully decorated Christmas tree sparkles with twinkling lights and shimmering ornaments. Delicious and indulgent feasts are prepared, filling the air with mouth-watering aromas. Generosity and kindness abound as people exchange thoughtful and heartfelt gifts. The joyful laughter of children fills the air, accompanied by the melodic sounds of Christmas carols. The winter scenery is breathtaking, with glistening snowflakes and frosty landscapes. The spirit of Christmas is truly magical, bringing warmth, joy, and togetherness to all.
21 tháng 6
Christmas is a magical and enchanting time of year. It is a joyous and festive occasion filled with love, happiness, and excitement. The air is filled with a warm and cozy atmosphere, as families come together to celebrate. The beautifully decorated Christmas tree sparkles with twinkling lights and shimmering ornaments. Delicious and indulgent feasts are prepared, filling the air with mouth-watering aromas. Generosity and kindness abound as people exchange thoughtful and heartfelt gifts. The joyful laughter of children fills the air, accompanied by the melodic sounds of Christmas carols. The winter scenery is breathtaking, with glistening snowflakes and frosty landscapes. The spirit of Christmas is truly magical, bringing warmth, joy, and togetherness to all.
N
2
TL :
Đáp án C
HT
C . 600
HT