Các câu hỏi tương tự
tim so tu nhien x,y sao cho:x /9 -3 / y = 1 / 18
cho A= 1/1^2 + 1/2^2+1/3^2 1/4^2+...+1/50^2. chung minhA<2
tinh tong S=3+3/2+3/2^2+...3/2^9
ban nao giup voi nhe to can on truoc
ChoA=1+2^1+2^2+2^3+...+2^2020+2^2021
a Tính 2.A
b chứng minhA=2^2022-1
a,A=1/1^2+1/2^2+1/3^2+1/4^2+...+1/50^2.chung minh rang a<2
b;2^1+2^2+2^3+...+2^30.chung minh rang B chia het cho21
A=1/2^2+1/3^2+...+1/50^2 , chung minh A<1
tính 3B :cho B=1+3+3^2+...+3^2006
chứng minhA={3^2007-1}:2
ChoA=1/1^2+1/2^2+1/3^2+1/4^2+...+1/50^2
Chung minh A <2
Chung minh A < 2:
A=1/1^2+1/2^2+1/3^2+1/4^2+.....+1/50^2
1. x^10 = 1^x
x^10 = x
(2*x-15)^5 = (2*x-15)^3
2. a co bao nhieu chu so ?
10^20 < a<10^21
3. Cho a = 1+2^2+2^3+..................+2^50
a)Tinh 2a
b)Tinh 2a-a
c)Chung minh a+1 la luy thua cua 2
chứng minhA=1/2-2/2^2+3/2^3-4/2^4+...+99/2^99-100/2^100<2/9