如图在等腰△ABC中,其中AB=AC,∠A=40°,P是△ABC内一点,且∠1=∠2,则∠BPC等于( )
A:110°
B:120°
C:130°
D:140°
已知fx=3cosx+3π2+cosx-3π2+sinx+π+a(a∈R,a为常数).
(1)若f(x)为奇函数,求a的值;
(2)若x∈R,求f(x)的最小正周期;
(3)若x∈0,π2时,f(x)的最大值为4,求a的值.