(lg5)²+2lg2-(lg2)²
=（1-lg2)^2+2lg2-(lg2)²
=1-2lg2+(lg2)²+2lg2-(lg2)²
=1
lg[根号下(3+根号5)+根号下(3-根号5)]=
[3+5^(1/2)]^(1/2)+[3-5^(1/2)]^(1/2)
={{[3+5^(1/2)]^(1/2)+[3-5^(1/2)]^(1/2)}^2}^(1/2)
={3+5^(1/2)+3-5^(1/2)+2*[4^(1/2)]}^(1/2)
=10^(1/2) 所以,
原式=lg[10^(1/2)]=1/2
log(2)5=log（3)5/log(3)2
log（5）3=log(3)3/log（3)5=1/log（3)5
log（2）25乘log（3）4乘log（5）9
=(2*log(2)5)(2*log(3)2)(2*log（5）3)
=8*log（3)5*log（5）3
=8*log（3)5*1/log（3)5
=8