观察下列各式: (a-1)(a+1)=a2-1 (a-1)(a2+a+1)=a3+a2+a-a2-a-1=a3-1 (a-1)(a3+a2+a+1)=a4+a3+a2+a-a3-a2-a-1=a4-1 根据观察的规律,解答下列问题: (1)填空: ①(a-1)(______)=a6-1; ②(a-1)(a11+a10+…+a+1)=______; ③(a-1)(an+an-1+an-2+…+a+1)=______. (2)已知:1+22+24+26+…+22006+22008+22010=
求:2+23+25+27+…+22007+22009的值. |