Alexis, Emma, and Li play in the school band. One plays the
flute. One plays the saxophone. One plays the drums. Alexis is
a 6" grader. Alexis and the saxophone player practice together
after school. Emma and the flute player are 5" graders. Who
plays the drums?
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so sánh M và N biết: M=\(\dfrac{100^{100}+1}{100^{99}+1}\) và N=\(\dfrac{100^{101}+1}{100^{100}+1}\)
\(\dfrac{M}{100}=\dfrac{100^{100}+1}{100.\left(100^{99}+1\right)}=\dfrac{100^{100}+1}{100^{100}+100}=\dfrac{100^{100}+100-99}{100^{100}+100}=1-\dfrac{99}{100^{100}+100}\)
\(\dfrac{N}{100}=\dfrac{100^{101}+1}{100.\left(100^{100}+1\right)}=\dfrac{100^{101}+1}{100^{101}+100}=\dfrac{100^{101}+100-99}{100^{101}+100}=1-\dfrac{99}{100^{101}+100}\)
Do \(100^{101}>100^{100}\)nên \(100^{101}+100>100^{100}+100\)
\(\Rightarrow-\dfrac{99}{100^{101}+100}>-\dfrac{99}{100^{100}+100}\)
\(\Rightarrow\dfrac{M}{100}>\dfrac{N}{100}\Rightarrow M>N\)
1,8dm=18cm
Diện tích đáy là: \(S_{Đáy}=\dfrac{1}{2}\cdot3\cdot4=6\left(cm^2\right)\)
Thể tích hình lăng trụ là: \(6\cdot18=108\left(cm^3\right)\)
Chu vi đáy là 3+4+5=12(cm)
Diện tích xung quanh là: \(12\cdot18=216\left(cm^2\right)\)
Diện tích toàn phần là: \(216+6\cdot2=216+12=228\left(cm^2\right)\)
Áp dụng tính chất của dãy tỉ số bằng nhau, ta được:
\(\dfrac{x-1}{2}=\dfrac{y-2}{3}=\dfrac{z-3}{4}=\dfrac{x+y+z-1-2-3}{2+3+4}=\dfrac{-34-6}{9}=\dfrac{-40}{9}\)
=>\(\left\{{}\begin{matrix}x-1=-\dfrac{40}{9}\cdot2=-\dfrac{80}{9}\\y-2=-\dfrac{40}{9}\cdot3=-\dfrac{120}{9}\\z-3=-\dfrac{40}{9}\cdot4=-\dfrac{160}{9}\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}x=-\dfrac{80}{9}+1=-\dfrac{71}{9}\\y=-\dfrac{120}{9}+2=-\dfrac{120}{9}+\dfrac{18}{9}=-\dfrac{102}{9}\\z=-\dfrac{160}{9}+3=-\dfrac{160}{9}+\dfrac{27}{9}=-\dfrac{133}{9}\end{matrix}\right.\)
\(3^{12}=3^{3.4}=\left(3^3\right)^4=27^4\)
\(5^8=5^{2.4}=\left(5^2\right)^4=25^4\)
Do \(27^4>25^4\) nên \(3^{12}>5^8\)
\(\dfrac{15}{2}-5\cdot\left(-\dfrac{3}{2}\right)^2:\dfrac{2}{9}+\left(-\dfrac{2}{3}\right)^2\)
\(=\dfrac{15}{2}-5\cdot\dfrac{9}{4}\cdot\dfrac{9}{2}+\dfrac{4}{9}\)
\(=\dfrac{15}{2}-\dfrac{405}{8}+\dfrac{4}{9}=-\dfrac{3073}{72}\)
1 Her collections are exciting and really attract me
2 My mum doesn't like watching films on TV
3 He usually takes a lot of beautiful photos
4 I like to keep the bottles after drinking the water