tính: A = \(\left(\dfrac{1}{2^2}-1\right).\left(\dfrac{1}{3^2}-1\right)-.\left(\dfrac{1}{100^2}-1\right)\)
giup mk nha
\(A=\left(\dfrac{1}{2^2}-1\right).\left(\dfrac{1}{3^2}-1\right)=\left(\dfrac{1}{100^2}-1\right)\)
\(=\left(\dfrac{1}{4}-\dfrac{4}{4}\right).\left(\dfrac{1}{9}-\dfrac{9}{9}\right)=..\left(\dfrac{1}{100^2}-\dfrac{10000}{10000}\right)\)
\(=\dfrac{-3}{4}.\dfrac{-8}{9}=...\dfrac{-9999}{10000}\)
\(\dfrac{\left(-1\right).3}{2^2}.\dfrac{\left(-2\right).4}{3^2}=-\dfrac{\left(-99\right).101}{100^2}\)
\(=\dfrac{\left(-1\right).\left(-2\right)=\left(-99\right)}{2.3...100}.\dfrac{3.4.5-.101}{2.3-.100}\)
\(=\dfrac{-1}{100}.\dfrac{101}{2}\)
\(=\dfrac{-101}{200}\)
=-101/200
(-3/2^2).(-8/3^2)...(-99/100^2)
=-1.3/2^2.-4/3^2...-9.11/100^2
=-1.-2.-3...-9/2.3.4.5...100 *3.4.5...11/2.3.4...100
bạn tự rút gọn ok
2+22+23+24+-.+229+230
Chứng tỏ nó chia hết cho 3 và 7
Help Me!!!
giúp người là việc tốt,vậy nên các bạn giúp mk nhé,mk cảm ơn trước!!!
Nhờ mọi người giúp mình vs!
Tìm x thuộc Q khi:
a)3x-1 =243
b)\(\left(\dfrac{2}{3}\right)^{x+1}=\dfrac{8}{4}\)
c) 3x+3x+2=270
d) \(\left(x-\dfrac{5}{2}\right)^2=144\)
e) \(\left(2x+1\right)^3=\dfrac{215}{27}\)
f) (2x-1)5 = -243
h) (27-1)2 = (2x-1)2
i) (2x+1)2 + (x+1)10 = 0
k) \(\dfrac{x-2}{5}=\dfrac{X+3}{2}\)
l) \(\dfrac{2}{x}=\dfrac{x}{50}\)
m) \(\dfrac{\left(x-3\right)}{4}=\dfrac{4}{x+3}\)
n) \(|x+\dfrac{3}{5}|-|x-\dfrac{7}{3}|\)
3) tìm x:
a) \(x^2=\dfrac{1}{16}\)
b)\(x^5\div x^2=\dfrac{-1}{64}\)
c)\(x^3\div x^2=\dfrac{32}{243}\)
d)\(\left(x^2\right)^2=\dfrac{81}{16}\)
Tìm x, biết:
\(\left(4x-3\right)^2=\left(4x-3\right)\)
Giúp mik nha.
Chìu nay mik nộp rồi .
\(\dfrac{2^{15}.9^4}{6^6.8^3}\)
bài 1 cho B = \(\dfrac{1}{2}+\left(\dfrac{1}{2}\right)^2+...+\left(\dfrac{1}{2}\right)^{99}\)
CMR :
a) B <1
b) B ko là số nguyên
Tìm n \(\in\) N biết: \(3^n.2^n=216\)
1,Tìm x thuộc Q biết
a,\(\left(3x-1\right)^4=81\)
b,\(\left(x+1\right)^5=32\)
Chung minh rang
a,76+75-74\(⋮\)11
b,109+108+107\(⋮\)222
a) (0, 5)2
b) (0, 5)3
c) (9, 7)0
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