计算或化简:(1)sin45°•cos60°-cos45°•sin30°;(2)5tan30°-2(cos60°-sin60°);(3)(32tan30°)2005•(22sin45°)2004;(4

题目简介

计算或化简:(1)sin45°•cos60°-cos45°•sin30°;(2)5tan30°-2(cos60°-sin60°);(3)(32tan30°)2005•(22sin45°)2004;(4

题目详情

计算或化简:
(1)sin45°•cos60°-cos45°•sin30°;
(2)5tan30°-2(cos60°-sin60°);
(3)(
3
2
tan30°)2005•(2
2
sin45°)2004
(4)
2
(2cos45°-tan45°)-(tan60°+sin30°)0-(2sin45°-1)-1
题型:解答题难度:中档来源:不详

答案

(1)原式=
2
2
×class="stub"1
2
-
2
2
×class="stub"1
2
=0;

(2)原式=5×
3
3
-2(class="stub"1
2
-
3
2

=
5
3
3
-2×
1-
3
2

=
5
3
3
-1+
3

=
8
3
-3
3


(3)原式=(
3
2
×
3
3
)2005•(2
2
×
2
2
)2004
=(class="stub"1
2
)2005•(2)2004=(class="stub"1
2
)2004•22004•class="stub"1
2

=class="stub"1
2


(4)原式=
2
(2×
2
2
-1)-(
3
+class="stub"1
2
)0-(2×
2
2
-1)-1
=2-
2
-1-class="stub"1
2
-1

=1-
2
-(
2
+1)
=-2
2

更多内容推荐