问题
解答题
计算:
(1)tan45°-2sin30°+cos230°;
(2)tan1°-tan89°+sin21°+sin289°.
答案
(1)原式=1-2×
+(1 2
)23 2
=1-1+3 4
=
;3 4
(2)原式=tan1°×
+(sin21°+cos21°)1 tan1°
=1+1
=2.
计算:
(1)tan45°-2sin30°+cos230°;
(2)tan1°-tan89°+sin21°+sin289°.
(1)原式=1-2×
+(1 2
)23 2
=1-1+3 4
=
;3 4
(2)原式=tan1°×
+(sin21°+cos21°)1 tan1°
=1+1
=2.