两道大一高数选择题?

感谢解答
2025-05-18 12:26:00
推荐回答(1个)
回答(1):

y=ax²,y'=2ax

y=lnx,y'=1/x

令切点为(m,n)

切点代入:am²=lnm①

切线斜率相等:2am=1/m②

由②得2am²=1③

将①代入③,2lnm=1,

lnm=1/2,m=e^(1/2)

a=1/(2m²)=1/(2e)


设f(x)=(2-x)g(x),g(x)=(1-x)(3-x)...(100-x)

f'(x)=-g(x)+(2-x)g'(x)

故f'(2)=-g(2) +0

=-(1-2)×(3-2)×...(100-2)

=98!