lim(n趋向于无穷)(x-a)sin(1/a-x)

求极限 lim x-无穷 sin(n+1)/(n+a) 判断极限是否存在lim [n+(-1)^n]/n n趋向于无穷 lim |x|/x x趋向于0 x趋向于无穷时 lim (3x-1)/(x^3 乘以 sin(1/x^2 )) lim(x趋向正无穷)[x]*sin(1\x)=? x趋向正无穷 lim[(x+a)/(x-a)]^x lim （n趋向无穷）（x/1+x)x次方 lim(x趋向于无穷)(1+3/x)^(x-3) (1)lim(x趋向0)[(1+x)^0.5+(1-x)^0.5-2]/x^2 (2)lim(n趋向无穷)sin[[(n 求lim (sin^2x+x)/(cos^2x-x) x趋向于无穷 lim x趋向于无穷(1-1/n)^n的极限 极限n趋向正无穷,求解定积分,lim（n趋向于无穷）定积分（0到1）x∧n／1+x∧2n lim(x趋向于正无穷)（x*sin(1/x)）=0 怎么用定义证明?