Ta có:
\(\frac{1}{2}\times\frac{2}{3}\times\frac{3}{4}\times...\times\frac{200}{201}\times x=\frac{1}{402}\)
\(\Rightarrow\frac{1}{201}\times x=\frac{1}{402}\Rightarrow x=\frac{1}{402}:\frac{1}{201}=\frac{1}{2}\)
Vậy x = 1/2.
k vs kb cho tớ nha!
1/2 . 2/3 . 3/4 .... . 200/201 . x = 1/402
\(\frac{1.2.3...200}{2.3.4...201}\). x = 1/402
1/201 . x = 1/402
x = 1/402 : 1/201
x = 1/2
Đặt \(C=\frac{1}{2}.\frac{2}{3}.\frac{3}{4}....\frac{200}{201}\)
\(\Rightarrow C=\frac{1.2.3...200}{2.3.4...201}\)
\(\Rightarrow C=\frac{1}{201}\)
\(\Leftrightarrow\frac{1}{201}.x=\frac{1}{402}\)
\(\Rightarrow x=\frac{1}{2}=0,5\)
