Question

Tìm x biết x+1/2+1/6+1/12+....+1/30=1

Answer 1

x + \(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}=1\)

x + \(\frac{1}{1x2}+\frac{1}{2x3}+\frac{1}{3x4}+\frac{1}{4x5}+\frac{1}{5x6}=1\)

x+ \(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}=1\)

x+ \(1-\frac{1}{6}=1\)

x+\(\frac{5}{6}=1\)

x=\(1-\frac{5}{6}\)

x=\(\frac{1}{6}\)

Answer 2

Tổng trên dạng: x+1/2+1/6+1/12+1/20+1/30=1

                <=>x+5/6=1

                <=>x=1/6

Answer 3

x=1                                                                                                                                                                                        em ko chắc lắm