Chứng minh rằng: a) loga( x+c ăn x^2-1)+loga( x-căn x^2-1)=0 ;
Chứng minh rằng:
a) loga(x+√x2−1)+loga(x−√x2−1)=0 ;
a) Ta có loga(x+√x2−1)+loga(x−√x2−1)
=loga[(x+√x2−1)(x−√x2−1)]
=loga[x2−(x2−1)]=loga1=0
Vậy loga(x+√x2−1)+loga(x−√x2−1)=0 .