What is the equation of the line normal to f(x)=(3x-1)(2x+4) at x=0?

1 Answer
Mar 17, 2016

10y = -x +40

Explanation:

Differentiate the formula to find the slope m. The line normal to the function is then -1/m. Given the point through which it passes, the equation of the line can then be calculated.
f(x) = (3x-1)(2x+4)
f(x)=6x^2 +10x -4
f'(x) = 12x +10

At x=0, f'(x) = 10
:. -1/m = -1/10

At x=0, f(x) = 4
4 = -x/10 +c
:. c= 4

the equation of the normal is 10y = -x +40