lg5^2+lg4+lg5*lg20+(lg2)^2
问题描述:
lg5^2+lg4+lg5*lg20+(lg2)^2
答
lg5^2+lg4+lg5*lg20+(lg2)^2
=lg(25*4)+(lg10-lg2)(lg10+lg2)+(lg2)^2
=lg100+(1-lg2)(1+lg2)+(lg2)^2
=2+1-(lg2)^2+(lg2)^2
=3