Let

Now,

Let

2x + 1 = A(x – 1) + B(x + 1)

Put x = 1

2 + 1 = A × 0 + B × 2

3 = 2B

Put x = – 1

– 2 + 1 = – 2A + B × 0

– 1 = – 2A

Therefore,