# Math Help - Point Of Inflection

1. ## Point Of Inflection

Show that for any cubic function of the form $y=ax^3+ bx^2 +cx +d$, there is a single point of inflection where the slope of the curve at that point is $c-(b^2/3a)$

2. Can you show us the work you completed so far?

3. u find second derivative of function
f"=c-(b^2/3a)? and thn u sovle for wht?
i dont even know i m rit or wronge

4. once you find the second derivative set it equal to 0 and solve for x

5. 6a+2b=0

6. but solve it for x

$x = \frac{-2b}{6a}$

Now replace x in the first derivative with the x you just solved for in the 2nd derivative and simplify

7. Originally Posted by ilovemymath
6a+2b=0
No, 6ax+ 2b= 0. Solve for x.