sin^230°+2sin^260°+tan45°-tan60°+cos^230°=
问题描述：
sin^230°+2sin^260°+tan45°-tan60°+cos^230°=
答
原式=sin²30°+2sin²60°+tan45°-tan60°+cos²30°
=(1/2)²+2×(√3/2)²+1-√3+(√3/2)²
=1/4+2×3/4+1-√3+3/4
=1/4+3/2+1-√3+3/4
=2+3/2-√3
=(7-2√3)/2