(adsbygoogle = window.adsbygoogle || []).push({}); If I am asked to find the constants a, b, c, d such that the graph of

f(x)= ax^3 + bx^2 + cx+ d has horizontal tangent lines at the points (-2, 1) and (0, -3).

I am not sure what to go about doing it...is that asking me to find what? (I dont know what do the constant stand for? in form of y= mx+b?)

I know though, the first thing I would do is, find the derivative of the function..."f(x)= ax^3 + bx^2 + cx+ d "

which would be...

f' (x) = 3 ax^2+ 2 bx+ c

then sub the value of x? x = (-2) into the last equation..

which will equal to

12 a- 4b+ c

nowwwwww? what do I do next?:grumpy:

and I have another q.

Given h= f 0 g, g(3)=7, g'(3)=4, f(2)=4, f'(7)=-6.

now how do I determine the h' (3)???

again i am half way through the answer...

I think thinking of solving it with product rule??

h(x)= f(g) x)) h(x)= f' (g(x) g'(x)

h' (x)= f' (g (3)= g'3= f' (7) (4) = (-6) (-4) = -24

soooo plz help???

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# Homework Help: Problme with word problems

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