若扇形圆心角的弧度数为2，且扇形弧所对的弦长也是2，则这个扇形的面积为（）A．1sin21B．2sin22C．1cos21D．2cos22

Question

若扇形圆心角的弧度数为2，且扇形弧所对的弦长也是2，则这个扇形的面积为（　　）

A．(1)/(sin21)
B．(2)/(sin22)
C．(1)/(cos21)
D．(2)/(cos22)

(1)/(sin21)
B．(2)/(sin22)
C．(1)/(cos21)
D．(2)/(cos22)(1)/(sin21)11sin21sin21sin21sin2121
(2)/(sin22)
C．(1)/(cos21)
D．(2)/(cos22)(2)/(sin22)22sin22sin22sin22sin2222
(1)/(cos21)
D．(2)/(cos22)(1)/(cos21)11cos21cos21cos21cos2121
(2)/(cos22)(2)/(cos22)22cos22cos22cos22cos2222

Answer 1

由题意得扇形的半径为：(1)/(sin1)．
又由扇形面积公式得，该扇形的面积为：(1)/(2)×2×(1)/(sin21)=(1)/(sin21)
故选A (1)/(sin1)111sin1sin1sin1．
又由扇形面积公式得，该扇形的面积为：(1)/(2)×2×(1)/(sin21)=(1)/(sin21)
故选A (1)/(2)111222×2×(1)/(sin21)111sin21sin21sin2121=(1)/(sin21)
故选A (1)/(sin21)111sin21sin21sin2121
故选A