2lg5+2/3lg8+lg5*lg20+lg²2
打错了
2lg5+2/3lg8+lg5*lg20+lg²2
打错了
2lg5+2/3lg8=lg5*lg20+lg²2
2lg5+2/3lg8=2lg5+2lg2=2lg10=2
lg5*lg20+lg²2=lg5*(lg2+lg10)+lg2*lg2=lg5*lg2+lg2*lg2+lg5=lg2(lg5+lg2)+lg5=lg2+lg5=lg10=1
或者原式=lg5*(lg4+lg5)+lg²2
=lg5*(2lg2+lg5)+lg²2
=lg²5+2lg2lg5+lg²2
=(lg5+lg2)²
=1²
=1