lim(e^x)x x趨向於負無窮時是多少是0嗎?

lim(e^x)x x趨向於負無窮時是多少是0嗎?


x趨近於負無窮時,e^-x和x都趨近於無窮,可用洛必達法則
lim(e^x)x=lim(x)/(e^-x)=lim1/(-e^-x)=0



x趨向於0,lim f(x)/x=1,f''(x)>0,證明f(x)>x


∵f(x)=x+o(x)∴f'(0)=1 f(0)=0
寫出f(x)的邁克勞林公式展開:
f(x)=f(0)+f'(0)x+f''(m)x^2 m介於0和x之間
f(x)=x+f''(m)x^2
∵f''(x)>0
f(x)-x>0



f(x)在x=2處連續,lim[f(x)/(x-2)]=3(X趨向於2),求f(2)和f'(2)
f(x)在x=2處連續,lim[f(x)/(x-2)]=3(X趨向於2),求f(2)和f'(2)


3=lim[f(x)/(x-2)](X趨向於2)=lim[f'(x)](X趨向於2)=f'(2)0/0型極限3=lim[f(x)/(x-2)](X趨向於2)可得1=limf(x)/[3(x-2)](X趨向於2)囙此f(2)=lim[f(x)](X趨向於2)=lim[3(x-2)](X趨向於2)=0;…