来自刘士荣的问题
求值:2723−2log23×log218+2lg(3+5√−−−−−−√+3−5√−−−−−−√)=()。A.17B.18C.19D.20
求值:2723−2log23×log218+2lg(3+5√−−−−−−√+3−5√−−−−−−√)=( )。A.17B.18C.19D.20
1回答
2019-06-23 08:56
求值:2723−2log23×log218+2lg(3+5√−−−−−−√+3−5√−−−−−−√)=()。A.17B.18C.19D.20
求值:2723−2log23×log218+2lg(3+5√−−−−−−√+3−5√−−−−−−√)=( )。A.17B.18C.19D.20
本题主要考查指数函数和对数函数的计算。因为2723=27−−√32=32=9,2log23×log218=3×(−log28)=3×(−3)=−9,2lg(3+5√−−−−−−√+3−5√−−−−−−√)=lg(3+5√−−−−−−√+3−5√−−−−−−√)2=lg(3+5√+3−5√+