Question

Find the sum A+B such that \(\frac{1}{n\left(n+2\right)}=\frac{A}{n+2}+\frac{B}{n}\)

Answer: A+B = ........

Answer 1

Answer: A + B = 1

Answer 2

An+Bn+2B=1

(=)n(A+B)=1-2B

(=)A+B=1-2B/n

theo mik là thế thôi...