$A\,=\dfrac{\left(-\dfrac 1 7\right)^n}{\left(-\dfrac 1 7\right)^{n-2}}\\\quad =\dfrac{\left(-\dfrac 1 7\right)^{n-2+2}}{\left(-\dfrac 1 7\right)^{n-2}}\\\quad =\dfrac{\left(-\dfrac 1 7\right)^{n-2}.\left(-\dfrac 1 7\right)^2}{\left(-\dfrac 1 7\right)^{n-2}}\\\quad =\dfrac{\left(-\dfrac 1 7\right)^2}{1}\\\quad =\left(-\dfrac 1 7\right)^2\\\quad =\dfrac{1}{49}$
Vậy $A=\dfrac{1}{49}$
`A=((-1/7)^n)/((-1/7)^(n-2))`
`=>A=((-1/7)^(n+2-2))/((-1/7)^(n-2))`
`=>A=((-1/7)^(n-2).(-1/7)^2)/((-1/7)^(n-2))` ( Áp dụng : `a^n . a^c=a^(n+c)` )
`=>A=(-1/7)^2` ( Rút gọn : `(-1/7)^(n-2)` )
`=>A=(-1/7)(-1/7)`
`=>A=1/49`
trái đất là 1 hình cầu trong chuyển động tự quay t=24h a,tìm ư=? b,tìm vxích đạo
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Phân tích đa thức thành nhân tử dùm mình nha
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$x^{2}$ + 6x + 8 ( hết) giúp mik vs!
a,1+2+3+...+2012+2013 b,6^2:43+2.5^2
Fill in each blank with a suitable relative pronoun (Who, that, which, where, whose) 1.I recently visited the school_______ I used to study five years ago. 2.I can’t understand the dance ________I saw at the festival last spring. 3.I’m really interested in the present______you gave me on my birthday. 4.Have you seen the photos________ I took at the camp last week? 5.The man ________ visited our school yesterday is a famous artist. 6.The girl _________ is standing over there is my younger sister. 7.Mary works for a company______makes toys for children. 8.The supermarket ________ was destroyed in the fire has now been rebuilt. 9.The bus ________ runs every twenty minutes goes to Tan Son Nhat airport. 10.An Architect is someone________ designs buildings. 11.I don’t like people _______often tell lies. 12.Alexander Bell was the man _______invented the telephone. 13.The sun________ is one of million of stars in the universe provides us with heat and light. 14.The book _______ you borrow yesterday is a present from my uncle on my 15th birthday
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