问题
解答题
(1)计算5
(2)cos60°-sin245°+
|
答案
(1)原式=5×
+5 5
×21 2
-5
×5 4 2 5
+35 5
=
+5
-5
+35 2 5
=9 5
.5
(2)原式=
-(1 2
)2+2 2
×(3 4
)2+1-13 3
=
-1 2
+1 2
×3 4 1 3
=
.1 4
(1)计算5
(2)cos60°-sin245°+
|
(1)原式=5×
+5 5
×21 2
-5
×5 4 2 5
+35 5
=
+5
-5
+35 2 5
=9 5
.5
(2)原式=
-(1 2
)2+2 2
×(3 4
)2+1-13 3
=
-1 2
+1 2
×3 4 1 3
=
.1 4