左边
=log(b+c)a+log(c-b)a
=lga/lg(b+c)+lga/lg(c-b)
=[lgalg(c-b)+lgalg(b+c)]/[lg(b+c)*lg(c-b)]
={lga[lg(c-b)+lg(b+c)]}/[lg(b+c)*lg(c-b)]
=(lga*lga^2)/[lg(b+c)*lg(c-b)]
=2(lga)^2/[lg(b+c)*lg(c-b)]
右边
=2log(b+c)a*log(c-b)a
=2lga/lg(b+c)*lga/lg(c-b)
=2(lga)^2/[lg(b+c)*lg(c-b)]
左边=右边