问题
解答题
计算:
①a4+(1-a)(1+a)(1+a2)
②(2x-1)2-(2x+1)2.
答案
①a4+(1-a)(1+a)(1+a2),
=a4+(1-a2)(1+a2),
=a4+1-a4,
=1;
②(2x-1)2-(2x+1)2,
=[(2x-1)+(2x+1)][(2x-1)-(2x+1)],
=(2x-1+2x+1)(2x-1-2x-1),
=4x•(-2),
=-8x.
计算:
①a4+(1-a)(1+a)(1+a2)
②(2x-1)2-(2x+1)2.
①a4+(1-a)(1+a)(1+a2),
=a4+(1-a2)(1+a2),
=a4+1-a4,
=1;
②(2x-1)2-(2x+1)2,
=[(2x-1)+(2x+1)][(2x-1)-(2x+1)],
=(2x-1+2x+1)(2x-1-2x-1),
=4x•(-2),
=-8x.