来自潘锋的问题
(2014•蚌埠三模)已知角a的终边与单位圆x2+y2=1交于P(12,y),则sin(π2+2a)=()A.-12B.1C.12D.-32
(2014•蚌埠三模)已知角a的终边与单位圆x2+y2=1交于P(12,y),则sin(π2+2a)=()
A.-12
B.1
C.12
D.-
32
1回答
2020-06-15 13:25
(2014•蚌埠三模)已知角a的终边与单位圆x2+y2=1交于P(12,y),则sin(π2+2a)=()A.-12B.1C.12D.-32
(2014•蚌埠三模)已知角a的终边与单位圆x2+y2=1交于P(12,y),则sin(π2+2a)=()
A.-12
B.1
C.12
D.-
32
∵点P在单位圆上
∴y=±
32