Các câu hỏi tương tự
tinh nhanh
1/10+1/30+1/60+1/100+1/150
Tinh:1/6+1/24+1/60+1/120+1/210+1/336+1/504+1/720
tinh tong: 1/42+1/56+1/72+1/90+...+1/182+1/210
tinh:1/42+1/56+1/72+1/90+1/110+1/132+1/156+1/182+1/210
Tinh nhanh :
\(\frac{101+100+99+....+2+1}{101-100+99-....+3-2+1}\)
\(G=\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+....+\frac{1}{3^{100}}\)
\(I=\frac{1}{2}+\frac{1}{14}+\frac{1}{35}+\frac{1}{65}+\frac{1}{104}+\frac{1}{152}\)
\(D=\frac{10}{100}+\frac{10}{150}+\frac{10}{210}+....+\frac{10}{1200}\)
\(P=\left(\frac{1}{51}+\frac{1}{52}+...+\frac{1}{100}\right):\left(\frac{1}{1.2}+\frac{1}{3.4}+\frac{1}{5.6}+...+\frac{1}{99.100}\right)\)
tinh p
tinh tong D= \(\frac{\frac{1}{51}+\frac{1}{52}+\frac{1}{53}+....+\frac{1}{100}}{\frac{1}{2}+\frac{1}{3.4}+\frac{1}{5.6}+...+\frac{1}{99.100}}\)
1, tinh tong
a, S = 1+2-3-4+5+6-7-8+...-100+101
b,C= 1.2+2.3+...+99.100
c, 1.2.3+2.3.4+...+98.99.100
2,tim so tu nhien x
a, 2+4+6+... +2x=210
b,x + (x-1)+(x-2)+...+(x-50)=255
c, (x+1)+(x+2)+...+(x+100)=5700
3,
S1 =1+2
S2=3+4+5
S3=6+7+8+9
hay tinh S99= ??