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计算:(1)259+(2764)−13-π0+2log36−log312−2lne(2)sin120°•cos330°-sin210°•cos(-60°)+tan675°.

题目详情
计算:
(1)
25
9
+(
27
64
 
1
3
0+2log36−log312−2ln
e

(2)sin120°•cos330°-sin210°•cos(-60°)+tan675°.
▼优质解答
答案和解析
(1)
25
9
+(
27
64
 
1
3
0+2log36−log312−2ln
e

=
5
3
+
4
3
−1+log336−log312−2ln
e

=
5
3
+
4
3
−1+1−1=2
(2)原式=sin(180°-60°)•cos(360°-30°)-sin(180°+30°)cos(60°)+tan(675°-720°)=sin60°cos30°+sin30°cos60°+tan(-45°)
=
3
2
×
3
2
+
1
2
×
1
2
−tan45°
=
3
4
+
1
4
−1=0.