如图,四边形OABC是菱形,若OA=2,∠AOC=45°,则B点的坐标是 ( )
A:(﹣2,2+2)
B:(2,2+2)
C:(-2,2+2)
D:(2,2+2)
(Ⅰ)求函数f(x)的单调区间;
(Ⅱ)当a>0时,若f(x)≥0对任意的x∈R恒成立,求实数a的值;
(Ⅲ)求证: ln1+2×3(3−1)2+ln1+2×32(32−1)2+⋯+ln1+2×3n(3n−1)2<2 .