設(shè)級(jí)數(shù)un收斂,試判定下列級(jí)數(shù)的斂散性: (un+10)
計(jì)算下列對(duì)弧長(zhǎng)的曲線積分:x2yzds,其中Γ為折線ABCD,這里A,B,C,D依次為點(diǎn)(0,0,0),(0,0,2),(1,0,2),(1,3,2).