题目内容
(1)解方程:x2-3x-4=0;
(2)计算:cos60°-
sin45°+tan230°.
(2)计算:cos60°-
2 |
(1)(x-4)(x+1)=0,
x-4=0或x+1=0,
所以x1=4,x2=-1;
(2)原式=
-
×
+(
)2
=
-1+
=
.
x-4=0或x+1=0,
所以x1=4,x2=-1;
(2)原式=
1 |
2 |
2 |
| ||
2 |
| ||
3 |
=
1 |
2 |
1 |
3 |
=
1 |
6 |
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