Find the equation for the normal line to f at the point (-4, f(-4)).
f(x)=-3-2x^3

Question

anonymous · Answer

didn't we just do this one?

anonymous · Answer

slightly diff

amistre64 · Answer

more elevation on the question tier :)

anonymous · Answer

I got y+125=(-1/96)(x+4)

anonymous · Answer

haha

anonymous · Answer

once you guys explain, I have to check if I understand by doing another example

anonymous · Answer

getting it correct is one thing, understanding another

amistre64 · Answer

f(-4)=-3-2(-4)^3

f'(x)=-6x^2; f'(-4) = -6(-4)^2

solve these and your good to go really

anonymous · Answer

steps exactly the same as before.  find 
$$f(-4)$$ for the second coordinate
$$f'(-4)$$ for the slope
and then take the negative reciprocal for the slope of the perpendicular line etc

amistre64 · Answer

f(-4) = 125;  f'(-4) = -96  right?

amistre64 · Answer

y = -(1/-96)(x+4)+125 is how to fill in the equation, then simplify as need be

anonymous · Answer

yes -96

anonymous · Answer

and 125

anonymous · Answer

does that mean I was wrong?

amistre64 · Answer

equation of the normal at x=-4 is:

y = (1/96)x +3001/24 if I did it right

anonymous · Answer

can you do it in the other form too pls: is y +125 or y - 125? etc

amistre64 · Answer

y - 125 = m(x+4) ; where m = (1/96)

anonymous · Answer

i sm not minus?