作业帮第12题.
来源：学生作业帮助网 编辑：作业帮 时间：2024/10/05 18:14:46
xMN0RUFI7p N mB 8bɺ Q n&RAWi͆?5'r1RwҘt\õYt\4M}/ʺ KjR
=va< cd*
1&ypL)0'ALB**99J b9`ҜS(QYe,L Zd
P!('2PGfr;ݠP=OJMTUV[ӉHH;YQ2c]?^ܞڻijT=^ ljj5LdմsWV:A~ 7p
l
第12题.
第12题.
第12题.
2sin20°+cos10°+tan20sin10°
=2sin20°+cos10°+sin20sin10°/cos20°
=2sin20°+(cos20°cos10°+sin20sin10°)/cos20°
=2sin20°+cos(20°-10°)/cos20°
=2sin20°+cos10°/cos20°
=(2sin20°cos20°+cos10°)/cos20°
=(sin40°+cos10°)/cos20°
=(sin40°+sin80°)/cos20°
=2sin[(40°+80°)/2]*cos[(40°-80°)/2]/cos20°
=2sin60°*cos20°/cos20°
=2*√3/2
=√3