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

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

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

17.-|||-如图, Delta AOD 与 Delta BOC 存在对顶角 angle AOD=angle BOC=dfrac (pi )(4) ,AC=2

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

cos A=dfrac (25)(31), 求 Delta ABC 的周长.

dfrac (2pi )(sqrt {3)} D. dfrac (pi )(6)

dfrac (2pi )(sqrt {3)}-|||-D. dfrac (pi )(6)

4.在 Delta ABC 中, cos C=dfrac (2)(3) =4 ,BC=3, 则 tan B= ()-|||-

tan dfrac (pi )(6)= ()-|||-

=-sqrt (2)(sin dfrac (pi )(6)+icos dfrac (pi )(6))的指数表达式为（ ）。A =-sqr