log2[根号下(7/48)]+log2(12)-1/2log2(42)-1?=log2{12*根号下(7/48)/[根号下(42)]}-1=log2{12*根号下[7/(48*42)]}-1=log2{12*根号下[7/(6*2*2*2**6*7)]}-1=log2根号下(1/2)-1=(1/2)log2(1/2)-1=(1/2)log2(2^-1)-1=(-...