问题
解答题
(1)计算:-12+2sin60°+
(2)用配方法解方程:x2-6x+4=0. |
答案
(1)-12+2sin60°+
-(cos45°-1)03 8
=-1+2×
+2-13 2
=-1+
+2-13
=
;3
(2)x2-6x+4=0
x2-6x=-4
x2-6x+9=-4+9
(x-3)2=5
x-3=±
,5
x1=3-
,x2=3+5
.5
(1)计算:-12+2sin60°+
(2)用配方法解方程:x2-6x+4=0. |
(1)-12+2sin60°+
-(cos45°-1)03 8
=-1+2×
+2-13 2
=-1+
+2-13
=
;3
(2)x2-6x+4=0
x2-6x=-4
x2-6x+9=-4+9
(x-3)2=5
x-3=±
,5
x1=3-
,x2=3+5
.5