Toán Lớp 6: (1/1×2+1/2×3+1/3×4+–+1/99×100)xX=33/100

TRẢ LỜI

1. ( \frac{1}{1xx2} + \frac{1}{2xx3} + \frac{1}{3xx4} + …. + \frac{1}{99xx100} )xx x = 33/100

   ( 1- 1/2 + 1/2 – 1/3 + 1/3 – 1/4 + …..+ 1/99 – 1/100)  xx x = 33/100

   ( 1 – 1/100)  xx x = 33/100

   99/100 xx x        = 33/100

                  x           = 33/100 : 99/100

                  x           = 33/100 . 100/99

                  x            = 1/3

   Vậy x = 1/3

   Trả lời
2. Giải đáp:

   (\frac{1}{1.2} + \frac{1}{2.3} + \frac{1}{3.4} + … + \frac{1}{99.100}) × x = \frac{33}{100}

   (1 – \frac{1}{2} + \frac{1}{2} – \frac{1}{3} + \frac{1}{3} – \frac{1}{4} + … + \frac{1}{99} – \frac{1}{100}) × x = \frac{33}{100}

   (1 – \frac{1}{100}) × x = frac{33}{100}

   \frac{99}{100} × x = \frac{33}{100}

   x = \frac{33}{100} : \frac{99}{100}

   x = \frac{1}{3}

   Vậy x = \frac{1}{3}.

   Chúc học tốt!!!

    

   Trả lời