(1-2/2.3)(1-2/3.4)(1-2/4.5)...(1-2/99.100)
Tính
+
1+(1+2)+(1+2+3)+...+(1+2+3+...+98) phần 1.2+2.3+3.4+...+98.99
Giúp vỚi mình cần gấp
tính: A=1/4+1/12+1/24+....+1/220
B=(1-1/4)x(1-1/9)x(1-1/16)x...x(1-1/100)
C=(1-2/2.3)x(1-2/3.4)x(1-2/4.5)x....x(1-2/99.100)
cả . ,x đều là nhân
tính
\(\left(1-\frac{2}{2.3}\right).\left(1-\frac{2}{3.4}\right).\left(1-\frac{2}{4.5}\right)...\left(1-\frac{2}{99.100}\right)\)
\(B=\left(1-\frac{2}{2.3}\right).\left(1-\frac{2}{3.4}\right).\left(1-\frac{2}{4.5}\right)....\left(1-\frac{2}{99.100}\right)\)
Tính A biết :
\(A=\left(1-\frac{2}{2.3}\right)\left(1-\frac{2}{3.4}\right)\left(1-\frac{2}{4.5}\right)....\left(1-\frac{2}{98.99}\right)\left(1-\frac{2}{99.100}\right)\)
\(\left(1-\frac{2}{2.3}\right)\left(1-\frac{2}{3.4}\right)\left(1-\frac{2}{4.5}\right)......\left(1-\frac{2}{99.100}\right)\)
Tính giá trị biểu thức \(M=\left(1-\frac{2}{2.3}\right).\left(1-\frac{2}{3.4}\right).\left(1-\frac{2}{4.5}\right)....\left(1-\frac{2}{99.100}\right)\)
Tính:
a. A = 1 + 2 + 3 + 4 +...+ (n-1) + n
b. A = 1.2 + 2.3 + 3.4 +...+ 99.100