log7[log3(log2x)]=log5tan45°则x^(-1/2)=?

问题描述:

log7[log3(log2x)]=log5tan45°
则x^(-1/2)=?

log5tan45°
=log5 1=0
log7[log3(log2x)]=0
log3(log2x)]=1
log2 x=3
x=8
x^(-1/2)=8^(-1/2)=√2/4