问题
解答题
(1)在Rt△ABC中,已知:∠C=90°,AC=2,BC=
(2)计算sin245°+cos245°-tan30°×sin60°. |
答案
(1)∵AC=2,BC=
,5
∴AB=
=3,22+
25
∴sinA=
=BC AB
;5 3
(2)sin245°+cos245°-tan30°×sin60°
=1+1-
×3 3 3 2
=2-1 2
=1
.1 2
(1)在Rt△ABC中,已知:∠C=90°,AC=2,BC=
(2)计算sin245°+cos245°-tan30°×sin60°. |
(1)∵AC=2,BC=
,5
∴AB=
=3,22+
25
∴sinA=
=BC AB
;5 3
(2)sin245°+cos245°-tan30°×sin60°
=1+1-
×3 3 3 2
=2-1 2
=1
.1 2