3/1*3+3/3*5+3/5*7+...+3/99*101

2 câu trả lời

Đáp án:

3/1*3+3/3*5+3/5*7+...+3/99*101

=3*2/1*3*2+3*2/3*5*2+3*2/5*7*2+...+3*2/99*101*2

=3/2(2/1*3+2/3*5+2/5*7+...+2/99*101)

=3/2(1/1-1/3+1/3-1/5+1/5-1/7+...+1/99-1/101)

=3/2(1/1-1/101)=3/2*(101/101+ -1/100)=3*100/2*101=3*50/1*101=150/101 

xin hay nhất ạ

Đáp án:

`150/101`

Giải thích các bước giải:

`3/(1. 3) + 3/(3. 5) + 3/(5. 7) + .... + 3/(99 xx 101)`

`= 2/2(3/(1. 3) + 3/(3. 5) + 3/(5. 7) + .... + 3/(99 xx 101))`

`= 3/2(2/(1. 3) + 2/(3. 5) + 2/(5. 7) + .... + 2/(99 xx 101))` 

`= 3/2(1/1 - 1/3 + 1/3 - 1/5 + 1/5 - 1/7 + .... + 1/99 - 1/101)`

`= 3/2.(1 - 1/101)`

`= 3/2. 100/101`

`= 150/101`