b) Cho B=4+3 mu 2+3 mu 3+3 mu 4+...+3 mu 2003+3 mu 2004 va C=3 mu 2005 so sanh B va C.
ai lam dung dau tien minh se tick cho . minh can gap lam
c) Tìm chữ số tận cùng của so A= 3 mu n+2-2 mu n+2+3 mu n-2 mu n. lam nhanh lem minh can gap lam ai lam dau tien va dung minh se tick cho
Tinh tong sau hop li :
A=2+2 mu 2 + 2 mu 3 + ............+2 mu 100
B=1+3 mu 2 + 3 mu 3 + .......... + 3 mu 2009
C = 4+ 4 mu 2 + 4 mu 3 + ...............+ 4 mu n
Giup minh voi sory may minh ko co dau minh dang can gap lam !!!
Lần sau viết cái đề rõ rõ ra nhs!!!
a) \(A=2+2^2+2^3+................+2^{100}\)
\(\Rightarrow2A=2^2+2^3+2^4+................+2^{100}+2^{101}\)
\(\Rightarrow2A-A=\left(2^2+2^3+..............+2^{100}+2^{101}\right)-\left(2+2^2+............+2^{100}\right)\)
\(\Rightarrow A=2^{101}-2\)
b) \(B=1+3+3^2+..................+3^{2009}\)
\(\Rightarrow3B=3+3^2+3^3+..................+3^{2009}+3^{2010}\)
\(\Rightarrow3B-B=\left(3+3^2+...............+3^{2010}\right)-\left(1+3+3^2+.............+3^{2009}\right)\)
\(\Rightarrow2B=3^{2010}-1\)
\(\Rightarrow B=\dfrac{3^{2010}-1}{2}\)
c) \(C=4+4^2+4^3+................+4^n\)
\(\Rightarrow4C=4^2+4^3+.................+4^n+4^{n+1}\)
\(\Rightarrow4C-C=\left(4^2+4^3+.............+4^n+4^{n+1}\right)-\left(4+4^2+............+4^n\right)\)
\(\Rightarrow3C=4^{n+1}-4\)
\(\Rightarrow C=\dfrac{4^{n+1}-4}{3}\)
\(A=2+2^2+2^3+...+2^{100}\)
\(2A=2^2+2^3+2^4+...+2^{101}\)
\(\Rightarrow2A-A=2^{101}-2\)
\(\Rightarrow A=2^{101}-2\)
Vậy \(A=2^{101}-2\).
\(B=1+3^2+3^3+...+3^{2009}\)
\(3B=3+3^3+3^4+...+3^{2010}\)
\(\Rightarrow3B-B=3^{2010}-7\)
\(\Rightarrow2B=3^{2010}-7\)
\(\Rightarrow B=\dfrac{3^{2010}-7}{2}\)
Vậy \(B=\dfrac{3^{2010}-7}{2}\).
\(C=4+4^2+4^3+...+4^n\)
\(4C=4^2+4^3+4^4+...+4^{n+1}\)
\(\Rightarrow4C-C=4^{n+1}-4\)
\(\Rightarrow3C=4^{n+1}-4\)
\(\Rightarrow C=\dfrac{4^{n+1}-4}{3}\)
Vậy \(C=\dfrac{4^{n+1}-4}{3}\).
So sanh :
a, 9 mu 5 va 27 mu 3
b, 3 mu 200 va 2 mu 300
c, 31 mu 11 va 17 mu 14
d, 199 mu 20 va 2003 mu 15
e, 2 mu 1993 va 7 mu 714
a, 9^5>27^3
b,3^200>2^300
c, 32^11<17^14
a, (1/2)mu x =64
b, x mu 3 +27 =0
c, 3 mu 2 /2 mu n =4
d, 625 / 5 mu n = 5
e, 27 mu n . 3 mu n = 3 mu 2
so sanh
a, 3 mu 200 va 2 mu 300
b, 2 mu 225 va 3 mu 150
so sanh
a, 16 mu 4 va 8 mu 5
b, 27 mu 7 va 9mu 10
c, 2 mu 300 va 3 mu 200
a) 164 = (24)4 = 216
85 = (23)5 = 215
Vì 216>215 nên 164>85
b) 277=(33)7=321
910=(32)10=320
Vì 321>320 nên 277>910
c) 2300=(23)100=8100
3200=(32)100=9100
Vì 8100 < 9100 nên 2300 < 3200
a,164>85
b,277>910
c,2300 <3200
nhé bạn
A
6^4=(2^4}^1=+2^64
8^5=(2^2}^5=2^1O
64 lớn hơn 1O
nên 2^64 lớn hơn 2^1O
vậy 6^4 lớn hơn 8^5
b
27^7=(3^3}^7=3^21
9^1O=(3^2}^1O=3^2O
21 lớn hơn 2O
nên 3^21 lớn hơn 3^2O
vậy 27^7 lớn hơn 9^1O
c
2^3OO=2^3.1OO=6^1OO
3^2OO=3^2.1OO=6^1OO
1OO=1OO
nên 6^1OO=6^1OO
vậy 2^3OO=3^2OO
bai 1; so sanh
a, 3 mu 600 va 2 mu 900 b, 2 mu 360 va 3 mu 240
c, 3 mu 236 va 2 mu 354
bai 2,tim x biet ;
a,5 mu x + 5 mu x +2 =650
b, 2 mu x +3 +5 nhan 2 mu x +2 - 2 mu x + 1 = 208
bai 3,tinh tong;A=3 + 3 mu 2 + 3 mu 3 +3 mu 4 +.........+3 mu 2019 +3 mu 2020
so sanh 2 mu 36 va 3 mu 27
9 mu 20 va 9999 mu 10
54 mu 4 va 21 mu 12
viet cach lam luon nha
Ta có:\(2^{36}\)và \(3^{27}\)
\(2^{36}=\left(2^4\right)^9=16^9\)
\(3^{27}=\left(3^3\right)^9=27^9\)
Vì \(16< 27\Rightarrow16^9< 27^9\)
Vậy....
b,\(9^{20}\)và \(9999^{10}\)
\(9^{20}=\left(9^2\right)^{10}=81^{10}\)
\(9999^{10}\)
Vì \(81< 9999\Rightarrow81^{10}< 9999^{10}\)
Vậy ...
c,\(54^4\)
\(21^{12}=\left(21^3\right)^4=9261^4\)
Vì \(54< 9261\Rightarrow54^4< 9261^4\)
Vậy...
1.tim x thuoc n biet:
a)3 mu x .3 b)x mu 20 = x c)2 mu x.16 mu 2=1024 d)64.4 mu x=16 mu 8
2.tim n thuoc n sao:
a)3 mu 2.3 mu n=3 mu 5 b)(2 mu 2:4).2mu n=4 c)32<2 mu n<128 d)2.16>_2 mu n>4
ai giai dung va nhanh minh tick cho
so chinh phuong la so bang binh phuong cua mot so tu nhien ( vi du 0 ,1,2,4,9,16,...0) moi tong sau day co so chinh phuong ko
a) 1mu 3 +2 mu 3
b)1mu 3+2mu 3 +3 mu 3
c)1 mu 3+ 2 mu 3 + 3 mu 3 +4 mu 3
tai minh ko biet go dau mu !