已知a=根号2+1,求a的三次方-a的平方-3a+2008的值,a=√2+1;a-1=√2;(a-1)²=2;a²-2a-1=0.所以：a³-a²+2008=a(a²-2a-1)+(a²-2a+1)+2007=2007
问题描述：
已知a=根号2+1,求a的三次方-a的平方-3a+2008的值,
a=√2+1;
a-1=√2;
(a-1)²=2;
a²-2a-1=0.
所以：a³-a²+2008=a(a²-2a-1)+(a²-2a+1)+2007=2007
答
a=√2+1;a-1=√2;(a-1)²=2;a²-2a-1=0;a²=2a+1;a³-a²-3a+2008=a(a²-a-3)+2008 =a(2a+1-a-3)+2008 =a(a-2)+2008 =...