3 7−+ 5 1+−+−2NNNN2N3(2(N++−−++3 32NNLIM 11N 6) NLIM 15.N 5)...

1) 3 7

+ 5 1

+

2

n

2

3

(

1

)(

)

3 3n

lim 1

n 6)

n

5

.

n 5)

lim 3