X 1    5.  6.     31 X 1 2X 1 3X ... 1 NX 1     ...

4. - TRAC NGHIEM
TRAC NGHIEM
4.

x 1

5.

6.     

3

1 x 1 2x 1 3x ... 1 nx

1

       

1 x 1 2x 1 3x

1

x

2x 1

lim

x

lim

x

2x 1

x 1

5