问题
解答题
计算或化简: (1)
(2)
(3)(sin60°+cos 45°)(sin 60°-cos 45°); (4)6tan230°-
|
答案
(1)原式=
×3
+3 2
×2
=2 2
+1=3 2
;5 2
(2)原式=
×1- 1 2 3 2
=3 3
×1 2
×2 3
=3 3
;1 3
(3)原式=sin260°-cos245°=(
)2-(3 2
)2=2 2
-3 4
=2 4
;1 4
(4)原式=6×(
)2-3 3
×3
-2×3 2
=2-2 2
-3 2
=2
-1 2
.2