一条弦将圆分成1:3两部分,则劣弧所对的圆心角为( )
A:30°
B:60°
C:90°
D:120°
dài tì
jì rán
yuán gù
suō huí
____
chéng rèn
fèn nù
jué zhāo
céng jīng
已知f(x)=ex,x∈R,a<b,记A=f(b)﹣f(a),B=12(b﹣a)(f(a)+f(b)),则A,B的大小关系是( )
___________ is not easy.