计算:(1)(1-sin60°+cos60°)(sin90°+cos60°-cos30°);(2)cos45°-sin30°cos45°+sin30°-cos40°sin50°.-数学

题目简介

计算:(1)(1-sin60°+cos60°)(sin90°+cos60°-cos30°);(2)cos45°-sin30°cos45°+sin30°-cos40°sin50°.-数学

题目详情

计算:
(1)(1-sin60°+cos60°)(sin90°+cos60°-cos30°);
(2)
cos45°-sin30°
cos45°+sin30°
-
cos40°
sin50°
题型:解答题难度:中档来源:不详

答案

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


(2)原式=
2
2
-class="stub"1
2
2
2
+class="stub"1
2
-1
=(
2
-1)2-1
=2-2
2

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