Toán Lớp 6: T=[1/2-1/3]x[1/2-1/5]x[1/2-2/7]-[1/2-1/99]

TRẢ LỜI

1. T=(1/2−1/3)(1/2−1/5)(1/2−1/7)…..(1/2−1/99)

   ⇒T=1/2·(1−2/3)1/2·(1−2/5)1/2·(1−2/7)…..1/2·(1−2/99)

   ⇒T=(1/2.49)·[(1−2/3)·(1−2/5)·(1-2/7)…(1−2/99)]

   ⇒T=(1/3)·(3/5)·(5/7)·….·(97/99)

   ⇒T=(49/2).(1/99)

   ⇒T=49/198

    

   Trả lời
2. T = ( 1/2 – 1/3 ) × ( 1/2 – 1/5 ) × ( 1/2 – 2/7 ) ….. ( 1/2 – 1/99 )

   ⇒ T = 1/2 × ( 1 – 2/3 ) × 1/2 × ( 1 – 1/5 ) × 1/2 × ( 1 – 3/7 ) …. 1/2 × ( 1 – 2/99 )   ⇒T = ( 1/2 × 4/9 ) × ( 1 – 2/3 ) × ( 1 – 2/5 ) …. ( 1 – 2/99 )

   ⇒ T = 49/2 × 1/99

   ⇒ 49/198

    

   Trả lời