求函数极限的2道题,详解,谢谢啦
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(1)
f(x)
=e^(x-1) ; x≥1
=x+a : x<1
f(1+)=f(1)=lim(x->1) e^(x-1) = e^0 =1
f(1-)=f(1)=lim(x->1) (x+a) = 1+a
lim(x->1) f(x) 存在
f(1+)=f(1-)
1=1+a
a=0
(2)
lim(x->-2) (3x^2+ax+a+3) /(x^2+x-2) 存在 (0/0)
3(-2)^2 +a(-2)+a+3=0
a=15
lim(x->-2) (3x^2+ax+a+3) /(x^2+x-2)
=lim(x->-2) (3x^2+15x+18) /(x^2+x-2)
=lim(x->-2) 3(x+2)(x+3) /[(x+2)(x-1)]
=lim(x->-2) 3(x+3) /(x-1)
=3(-2+3)/(-2-1)
=-1
f(x)
=e^(x-1) ; x≥1
=x+a : x<1
f(1+)=f(1)=lim(x->1) e^(x-1) = e^0 =1
f(1-)=f(1)=lim(x->1) (x+a) = 1+a
lim(x->1) f(x) 存在
f(1+)=f(1-)
1=1+a
a=0
(2)
lim(x->-2) (3x^2+ax+a+3) /(x^2+x-2) 存在 (0/0)
3(-2)^2 +a(-2)+a+3=0
a=15
lim(x->-2) (3x^2+ax+a+3) /(x^2+x-2)
=lim(x->-2) (3x^2+15x+18) /(x^2+x-2)
=lim(x->-2) 3(x+2)(x+3) /[(x+2)(x-1)]
=lim(x->-2) 3(x+3) /(x-1)
=3(-2+3)/(-2-1)
=-1
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x趋于0时,1/x∧2等于什么
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