\(A=\frac{100}{3}+\frac{100}{3^2}+\frac{100}{3^3}+\frac{100}{3^4}\)
\(\Rightarrow3A=100+\frac{100}{3}+\frac{100}{3^2}+\frac{100}{3^3}\)
\(\Rightarrow3A-A=100+\left(\frac{100}{3}-\frac{100}{3}\right)+\left(\frac{100}{3^2}-\frac{100}{3^2}\right)+\left(\frac{100}{3^3}-\frac{100}{3^2}\right)-\frac{100}{3^4}\)
\(\Rightarrow2A=100-\frac{100}{3^4}=100.\left(1-\frac{1}{3^4}\right)=100.\frac{80}{81}\)
\(\Rightarrow A=\frac{100.80}{2.81}=\frac{4000}{81}\)
CMR:
1/3+2/3^2+3/3^3+...+100/3^100<3/4
giup minh nha gap lam do.....
a)A=1-2+3-4+...+99-100
b)B=1-2-3+4+5-6-7+...+97-98-99+100
c)C=2100-299s-998-...-22-2-1
giup mik vs a
a) Hãy tính : [-1/7];[3,7];[-4];[-43/10]
b) Cho x = 3,7. So sánh :
A = [x] + [x+1/5] + [x+2/5] + [x+3/5] + [x+4/5] và B = [5x]
c) Tính [100/3] + [100/32] + [100/33] + [100/34]
d) Tính [50/2] + [50/22] + [50/23] + [50/24] + [50/25]
Giúp mik nha
Toán HS giỏi đấy
Thank you
[1/100-1^2]ư.[1/100-(1/2)^2].[1/100-(1/3)^2]...[1/100-(1/20)^2]
Giải đầy đủ cho mik nha
A = 1 + 3/2^3 + 4/2^4 + 5/2^5 + ..... + 100/2^100
Nhanh nha
Tính:[100/3]+[100/3^2]+[100/3^3]+[100/3^4]
tính [100/3]+[100/3^2]+[100/3^3]+[100/3^4]ư
(100/3)+(100/32)+(100/33)+(100/34)
100/3+100/3^2+100/3^3+100/3^4
Tinh