If `f:NtoR,` where `f(n)=a_(n)=(n)/((2n+1)^(2))` write the sequence in ordered pair from.

Explanation

Here, `a_(n)=(n)/((2n+1)^(2))`
On putting `n=1,2,3,4,"….."` successively, we get
`a_(1)=(1)/((2*1+1)^(2))=(1)/(9), a_(2)=(2)/(2*2+1)^(2)=(2)/(25)`
`a_(3)=(3)/(2*3+1)^(2)=(3)/(49),a_(4)=(4)/(2*4+1)^2=(4)/(81)`
`" "vdots " "vdots" "vdots`
Hence, we obtain the sequence `(1)/(9),(2)/(25),(3)/(49),(4)/(81),"...."`
Now, the sequence in ordered pair form is
`{(1"",(1)/(9)),(2"",(20)/(25)),(3"",(3)/(49)),(4"",(4)/(81)),"..."}`