1+1+1+1+1+1+1+1+1+1+1+1+2+2+2+3374580352312321231231283490527035^50- -123456789=1+?
1+1+1+1+2++23+45+654+3443+124715417216189472827+4241567854+1456789+747214176 -2345678998765+12345678^11111111111111123456789+123456789-123456789
1+1+2+3..........,...........+1098+1075=123456789
1+1=
2+2=
123456789+987654321=
1+1=2
2+2=4
123456789+987654321=1111111110
k cho mình nha
1+1=2
2+2=4
123456789+987654321=1111111110
Chúc bạn Hk tốt!!!!
1 + 1 = 2
2 + 2 = 4
123456789 + 987654321 = 1111111110
\(\frac{1}{2^2}+\frac{1}{4^2}+\frac{1}{6^2}+..+\frac{1}{100^2}=\frac{1}{2^2}\left(1+\frac{1}{2^2}+\frac{1}{3^2}+...+\frac{1}{50^2}\right)\)
Có \(\frac{1}{2^2}< \frac{1}{1.2}=1-\frac{1}{2}\) \(\frac{1}{3^2}< \frac{1}{2.3}=\frac{1}{2}-\frac{1}{3}\)....v........v............ \(\frac{1}{50^2}< \frac{1}{49.50}=\frac{1}{49}-\frac{1}{50}\)
Cộng lại \(1+\frac{1}{2^2}+\frac{1}{3^2}+...+\frac{1}{50^2}< 1+1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{49}-\frac{1}{50}=2-\frac{1}{50}\)
\(\Rightarrow VT< \frac{1}{2^2}\left(2-\frac{1}{50}\right)=\frac{1}{2}-\frac{1}{2^2.50}< \frac{1}{2}\left(Đpcm\right)\)
ủa toán lớp mấy chứ ko phải lớp 1
uk ko phải toán lớp 1
Thực Hiện phép tính
B= 1 + 1/2(1+2) + 1/3 (1+2+3)+1/4(1+2+3+4)+....+1/50(1+2+3+....+50)
\(B=1+\dfrac{1}{2}\cdot\dfrac{2\cdot3}{2}+\dfrac{1}{3}\cdot\dfrac{3\cdot4}{2}+...+\dfrac{1}{50}\cdot\dfrac{50\cdot51}{2}\)
\(=1+\dfrac{3}{2}+\dfrac{4}{2}+...+\dfrac{51}{2}\)
\(=\dfrac{50\cdot\dfrac{\left(51+2\right)}{2}}{2}=50\cdot\dfrac{53}{4}=662.5\)
1+[1+2]+[1+2+3]+...+[1+2+3+...+50]/1*50+2*49+...+50*1
giả sử : 1 + 1 = 11
2 + 1 = 21
3 + 9 = 39
hỏi : 123456789 + 987654321 = ?
1/2*1/2+1/3*1/3+1/4*1/4+....+1/50*1/50
So sánh 1/2*1/2+1/3*1/3+1/4*1/4+...+1/50*1/50 với 1
Gọi tổng trên là A
A = 1/22+1/33+.....+1/502
A = 1/2.2 + 1/3.3 +.....+ 1/50.50
A < 1/1.2 + 1/2.3 +.....+ 1/49.50
A < 1 - 1/2 + 1/2 - 1/3 +.......+ 1/49 - 1/50
A < 1 - 1/50
A < 49/50 < 1
=> A < 1
Ai k mk mk k lại
A=(1/2)*(1/2)+(1/3)*(1/3)+...+(1/50)*(1/50) = 1/(2*2)+1/(3*3)+1/(4*4)+...+1/(50*50) < 1/(1*2)+1/(2*3)+...+1/(49*50)
Mà 1/(1*2)+1/(2*3)+...+1/(49*50) = 1-1/2+1/2-1/3+1/3-1/4+...+1/49-1/50 =1-1/50 <1
=> A<1