Question

CM :

\(\frac{1}{a}=\frac{1}{a+1}+\frac{1}{a.\left(a+1\right)}\)               (a \(\in\) Z ; a khác 0)

Answer 1

ĐK: a khác -1

\(\frac{a}{a\left(a+1\right)}+\frac{1}{a\left(a+1\right)}=\frac{a+1}{a\left(a+1\right)}=\frac{1}{a}\left(đpcm\right)\)

Answer 2

\(\frac{1}{a+1}+\frac{1}{a.\left(a+1\right)}=\)\(\left(\frac{1}{a}+1\right)\left(\frac{1}{a+1}\right)=\frac{a+1}{a}.\frac{1}{a+1}=\frac{1}{a}\)

Answer 3

(1\a+1)+(1\a(a+1))=a\a(a+1)+1\a+1=a+1\a(a+1)=1\a