问题 解答题
计算或解方程:
(1)
2
cot30°-1
-4sin45°-(
3
-1)+
8

(2)2cos60°+2sin30°+4tan45°;
(3)(x-1)2=2(x-1);
(4)x2+3=2(x+2);
(5)(tan21°-tan69°+sin^33°+cos^33°)-
sin6°
cos6°
-
1
cot84°
答案

(1)原式=

2
3
-1
-4×
2
2
-
3
+1+2
2
=
3
+1-2
2
-
3
+1+2
2
=2;

(2)原式=2×

1
2
+2×
1
2
+4×1=6;

(3)∵(x-1)2=2(x-1),

∴(x-1)(x-1-2)=0,

∴x1=1,x2=3;

(4)∵x2+3=2(x+2),

∴x2-2x+1=2,

∴(x-1)2

2

∴x1=1+

2
,x2=1-
2

(5)原式=(1+1)×tan6°×

1
tan6°
=2.

单项选择题
单项选择题