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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 6: Tính giá trị của biểu thức sau C= ( 1- 1 )x (1- 1. )x (1- 1. )x (1- 1. )x… x 1931. 1932. 1

Toán Lớp 6: Tính giá trị của biểu thức sau
C= ( 1- 1 )x (1- 1. )x (1- 1. )x (1- 1. )x… x
1931. 1932. 1933. 1934.
(1- 1. )
2019

Comments ( 2 )

  1. C = (1 – $\frac{1}{1931}$) × (1 – $\frac{1}{1932}$) × (1 + $\frac{1}{1933}$) × (1 + $\frac{1}{1934}$) × … × (1 – $\frac{1}{2019}$)
      = $\frac{1930}{1931}$ × $\frac{1931}{1932}$ × $\frac{1932}{1933}$ × $\frac{1933}{1934}$ × … × $\frac{2018}{2019}$ 
      = $\frac{1930 × 1931 × 1932 × 1933 × … × 2018}{1931 × 1932 × 1933 × 1934 × … × 2019}$ 
      = $\frac{1930}{2019}$ 

  2. C = (1 – 1/1931) xx (1 – 1/1932) xx (1 – 1/1933) xx … xx (1-1/2019)
    = 1930/1931 xx 1931/1932 xx 1932/1933 xx … xx 2018/2019
    = (1930 xx 1931 xx 1932 xx 1933 xx … xx 2017 xx 2018)/(1931 xx 1932 xx 1933 xx… xx 2018 xx 2019)
    = 1930/2019

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222-9+11+12:2*14+14 = ? ( )