Question

已知函数f(x)＝3x-lnx,求这个函数的导数f'(x)

Answer 1

(1)

f'(x)=3-1/x

(2)

f'(1)=3-1=2

f(x)=3

切点(1,3)

切线:y-3=2(x-1)

y=2x+1