Question

求函数给定点的导数一.f(x)=x的1/4方,x=1二.f(x)=3(x+1)x的平方,x=1三.f(x)=2x平方+5

Answer 1

1.

f'(x)=1/4*x^(-3/4)

f'(1)=1/4

2.

f'(x)=3(3x^2+2x)=9x^2+6x

f'(1)==9+6=15

3.

f'(x)=4x+5

f'(2)=4*2+5=13

4.

f'(x)=2x(2x+3)+(x^2+1)*2=6x^2+6x+2

f'(2)=6*4+6*2+2=38

5.

y'=18x

x=1/3时,y=9/9-1=0,y'=2

y=2(x-1/3)=2x-2/3

6.

y'=1/x

x=1时,y=0,y'=1

y=1(x-1)=x-1