问题
解答题
计算:①cos230°-tan60°•cos45°+sin230° ②(-2)2×
|
答案
①原式=(
)2-3 2
×3 3
+(2 2
)21 2
=
-3 4
+6 6 1 4
=1-
;6 6
②原式=4×2
-163
+12+3 8(2+
)3 (2-
)(2+3
)3
=8
-163
+12+16+83 3
=28.
计算:①cos230°-tan60°•cos45°+sin230° ②(-2)2×
|
①原式=(
)2-3 2
×3 3
+(2 2
)21 2
=
-3 4
+6 6 1 4
=1-
;6 6
②原式=4×2
-163
+12+3 8(2+
)3 (2-
)(2+3
)3
=8
-163
+12+16+83 3
=28.