Question

设a>0是常数,连续函数f(x)满足limx→正无穷f(x)=b,y

两道高数题 极限和连续函数
⒈设lim(x→x0):f(x)=a>0,lim(x→x0):g(x)=b,证明：lim(x→x0):f(x)^g(x)=a^b
⒉设0

Answer 1

f(x)^g(x)=e^[g(x).lnf(x)]
lim(x→x0):f(x)^g(x)
=e^{lim(x→x0):[g(x).lnf(x)]}
=e^{[lim(x→x0):g(x)][lim(x→x0):lnf(x)]}
=e^[b.ln a]
=a^b
y'=1-acosx
因为0