# What is the equation of the line normal to #f(x)=6x^3+2x # at #x=3#?

##### 1 Answer

Dec 18, 2016

#y=-x/164+27555/164#

#### Explanation:

Given -

#y=6x^3+2x#

#dy/dx=18x^2+2#

Slope, exactly at

At

This is the slope of the tangent

Slope of the normal

At

We have to find the equation of the line passing through the point

#mx+c=y#

#-1/164(3)+c=168#

#c=168+3/164=(27552+3)/164=27555/164#

#y=-x/164+27555/164#