Question

英文的导数题Let f(x)=8x+20/(x^2).Then the equation of the tangent

Answer 1

给出的那个点的坐标(2,21)都是多余的,给其中一个坐标就行了

f'(x)=8-40/(x^3)

so

f'(2)=3,

m=3

and the equation of the tangent line can be as below:

y-21=3(x-2)

solve it:

y=3x+15

so

b=15

题目我能看懂,但是如何用英语表达解题步骤,还想请教请教你.