1, A = 1/2 + 1/6 + 1/12 + .. + 1/42
= 1/1.2 + 1/2.3 +1/3.4 + 1/4.5 + 1/5.6 + 1/6.7
= 1/1 - 1/2 + 1/2 - 1/3 + 1/3 - 1/4 + 1/4 - 1/5 + 1/5 - 1/6 + 1/6 - 1/7
= 1 - 1/7
= 6/7
Tính nhanh
A = \(\dfrac{1}{2}\) + \(^{\dfrac{1}{3}}\) + \(\dfrac{1}{6}\) + \(\dfrac{1}{12}\) + \(\dfrac{1}{15}\) + \(\dfrac{1}{20}\) + \(\dfrac{1}{25}\) + \(\dfrac{1}{30}\) + \(\dfrac{1}{35}\) + \(\dfrac{1}{42}\) + \(\dfrac{1}{56}\) + \(\dfrac{1}{63}\)
Mình đang cần gấp , mong mn giúp mình với ạ
Tính nhanh
A= 1+1/2+1/3+1/6+1/12+1/15+1/20+1/30+1/35
Tính
1. A= 1/2+1/6+1/12+/1/20+1/30+1/42+1/56
2. B = 3/2+5/6+7/12+-9/20+11/30-13/42+15/56
thực hiện phép tính:
A=1/2+1/6+1/12+1/20+1/30+1/42-(3-2/6)
Tính nhanh
1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42
tính A=1/2+1/6+1/12+1/20+1/30+1/42 (nhớ trình bày cách giải nhé)
1. tính A= 1/6+1/12+1/20+1/30+1/42+...+1/110
Tính: 1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56
Tính nhanh :A=1/6+1/12+1/20+1/30+1/42+1/56
