chung tỏ 3/1nhan 4+3/4nhan 7+...+3/91nhan 94
chung minh 3/1nhan 4+ 3/4nhan 7+...+3/91nhan 94<1
chung minh 3/1nhan4 +3/4nhan 7+...+3/91 nhan94<1
chung minh 1nhan 2 nhan 3 nhan 4 nhan 5 nhan...nhan19 nhan20 chia het cho 100
Ta có 1.2.3.4....19.20
=10.(2.5).1.3.4.6...9.11....19.20
=10.10.1.3.4.6...9.11....20
=100.1.3.4.6...9.11....20 \(⋮100\)(đpcm)
tk mk nha bn
*****Chúc bn hk giỏi*****
2nhan(x-4)+4nhan(x-3)-x+1=3nhan(2x-3)-7
Chứng tỏ rằng 5*2^3+4*3^3-94-3)^2
tim x biet: 4nhan[x-3]-x=3
4. (x-3) - x = 3
4x - 12 - x = 3
3x - 12 = 3
3x = 3+12
3x = 15
x= 15:3
x = 5
14 chia cho 3 bang 4nhan may
1nhan 3 nhan 5 nhan7 nhan 9 .........nhan 2009 nhan 20011
A= 3/1*4 + 3/4*7 + 3/7*10 + .......+ 3/94*97
giúp mình ha
\(A=\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+...+\frac{3}{94.97}\)
\(A=1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+....+\frac{1}{94}-\frac{1}{97}\)
\(A=1-\frac{1}{97}\)
\(A=\frac{96}{97}\)