17.-|||-如图, Delta AOD 与 Delta BOC 存在对顶角 angle AOD=angle BOC=dfrac (pi )(4) ,AC=2 ,=2sqrt (2) 且 BC=AD-|||-(1)证明:O为BD中点;-|||-(2)若 sqrt (5)sin 2A+cos B=sqrt (5) ,求OC的长.

在 Delta ABC 中, angle A=dfrac (pi )(6),在 Delta ABC 中, angle A=dfrac (pi )(6),

2.已知:如图,在 Delta ABC 中, angle BAE=angle CAE angle ADC=(90)^circ angle B=(40)^cir

(2angle(pi)/(12))^3=8angle(pi)/(4).A. 对B. 错

=2sqrt (2) D. Delta PAC 的面积为 sqrt (3)

如图,在 Delta ABC 中, angle BAE=angle CAE ,-|||-angle ADC=(90)^circ angle B=(40)^ci

设随机变量X的概率密度为(x)=dfrac (1)(2sqrt {pi )}(e)^-dfrac ({(x-3)^2)(4)}((x)=dfrac (1)(2s

[题目] Delta ABC 中-|||-angle B=angle A+(10)^circ angle C=angle B+(10)^circ 求 Del

. _(Y)(y)=dfrac (1)(2sqrt {2pi )}(e)^-dfrac (y{2)} ,gt 0-|||-bigcirc ._(Y)(y)=d

(湖北武汉江夏期中)已知: AD=AC =AE, AD交BC于点F.-|||-(1)如图1,若 angle BAD=angle CAE, 设DE交BC于点N,交

sqrt (2)pi -|||-C. dfrac (sqrt {2pi )}(4)-|||-D. dfrac (sqrt {2pi )}(8)