Ta có: \(\left(\frac{1}{2}+1\right).\left(\frac{1}{3}+1\right).....\left(\frac{1}{99}+1\right)\)
\(=\frac{3}{2}.\frac{4}{3}.\frac{5}{4}.....\frac{100}{99}=\frac{3.4.5..100}{2.3.4...99}=\frac{100}{2}=50\)
Vậy \(\left(\frac{1}{2}+1\right)\left(\frac{1}{3}+1\right)......\left(\frac{1}{99}+1\right)=50\)
CHÚC BẠN HỌC TỐT
(1+97)*(1+97/2)*(1+97/3)*(1+97/4)... ... ...(1+97/99)
(1+99)*(1+99/2)*(1+99/3)*(1+99/4)... ... ...(1+99/97)
1/1*2-1/1*2*3+1/2*3-1/2*3*4+1/3*4-1/3*4*5+...+1/99*100-1/99*100*101
1/1*2*3+1/2*3*4+1/3*4*5+........+1/98*99*100=1/k*(1/1*2-1/99*100)
1+(1+2)+(1+2+3)+...+(1+2+3+4+...+99+100)/(1*100+2*99+...+99*2+100*1)*2013
tinh tong gia tri bieu thuc :
a)A=1+1/3+1/5+...+1/97+1/99/1/1*99+1/3*97+1/5*95+...+1/97*3+1/99*1
b)B=1/2+1/3+1/4+...+1/100/99/1+98/2+97/3+...+1/99
Help me!!!Thanks các pạn nhìu nha.
Tính hợp lý:
1)(1/2+1/3+1/4+...+1/100):(99/1+98/2+97/3+...+1/99)
2)A=1/3+1/3^2+1/3^3+...+1/3^99
3)4^5.9^4-2.6^9/2^10.3^8+6^8.20
a,(1-1/2)*(1-1/3)*(1-1/4)....(1-1/99)*(1-1/100)
b,(1+1/2)*(1+1/3)*(1+1/4)....(1+1/99)*(1+1/100)
tim tich a)(1/2+1).(1/3+1).(1/4+1). ... (1/99+1)
b)(1/2-1).(1/3-1).(1/4-1). ... .(1/99-1).(1/100-1)
CMR
1/2-1/4+1/8-1/16+1/32-1/64<1/3
1/3-2/3^2+3/3^3+4/3^4+...+99/3^99<3/16
Bài 4: Tính tổng 1) 1 + (-2) + 3 + (-4) + . . . + 19 + (-20) 2) 1 – 2 + 3 – 4 + . . . + 99 – 100 3) 2 – 4 + 6 – 8 + . . . + 48 – 50 4) – 1 + 3 – 5 + 7 - . . . . + 97 – 99 5) 1 + 2 – 3 – 4 + ... + 97 + 98 – 99 - 100
