知x=根2+1,则log4(x3次方-x-6)=?要过程~

来源:百度知道 编辑:UC知道 时间:2024/05/22 03:28:49

知x=√2+1,则log4(x^3-x-6)=?要过程~

log4(x^3-x-6)=?

x^3-x-6= =(√2+1)( √2+1)( √2+1)-(√2+1)-6
=(3+2√2)(√2+1)-(√2+1)-6
=(2+2√2)(√2+1)-6
=2√2+2+4+2√2-6
=6+4√2-6
=4√2

log4(x^3-x-6)=log4(4√2)=log4 4 +log4 √2
= 1 +log2^2 2^1/2=1+1/4=5/4

题看不懂,能不能再清楚些