1/2lg32/49-4/3lg√8+lg√245
=(1/2)*(lg32-lg49) - (4/3)*(1/2)*lg8 +(1/2)*lg245
=(1/2)*(5lg2- lg49) - (2/3)*3lg2 +(1/2)*(lg49+lg5)
=(5/2)*lg2 - 2lg2 +(1/2)lg5
=(1/2)*(lg2+lg5)
=1/2