1.按定义证明下列极限:-|||-(1) lim _(xarrow -infty )dfrac (6x+5)(x)=6;-|||-(2) lim _(xarrow 2)((x)^2-6x+10)=2;-|||-(4) lim _(xarrow {2)^-}sqrt (4-{x)^2}=0;-|||-(5) lim _(xarrow {x)_(0)}cos x=cos (x)_(0).-|||-2.根据定义2叙述 lim _(Delta arrow {x)_(0)}f(x)neq A.-|||-3.设 lim _(xarrow {x)_(0)}f(x)=A, 证明 lim _(harrow 0)f((x)_(0)+h)=A.-|||-4.证明:若 lim f(x)=

1.按定义证明下列极限:-|||-(1) lim _(xarrow +infty )dfrac (6x+5)(x)=6;-|||-(2) lim _(xarro

1.按定义证明下列极限:-|||-(1) lim _(xarrow -infty )dfrac (6x+5)(x)=6;-|||-(2) lim _(xarro

1.按定义证明下列极限:-|||-① lim _(xarrow infty )dfrac (6x+5)(x)=6;-|||-lim _(xarrow 2)((x

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求下列函数的极限( 1 )lim _(xarrow infty )dfrac ({(2x-1))^10((7x+2))^20}(5{x)^30}( 2 )lim

求下列函数的极限：（1）lim _(xarrow +infty )dfrac ({(2x-1))^10((7x+2))^20}(5{x)^30}（2）lim _