Inflection Points....PLEASE HELP!

[nikchic5]

Which statements are correct?

a. The grah of y= (x^3-1) / (x^3+1) has an inflection point at (-2, 9/7)
b. The graph of y=x sqrt(2-x^2) has an inflection point at (-1,1)
c. The graph of y= x^5/3 - 5^2/3 has an inflecdtion point at (-1,-6)
d. The graph of y=(x^2) / (x^2 +9) has an inflection point at (sqrt3 , 1/4)
e. The graph of (x^3-1) / (x^3+1) has an inflection point at (1,0)

Thanks so much to anyone who can help!

 

[stapel]

What inflection points did you find after taking the second derivative?

Please reply showing your steps. Thank you.

Eliz.

 

[nikchic5]

Ok...

I got the answers that are correct are a c and d are those correct?
Thanks!

 

[stapel]

I got the answers that are correct are a c and d are those correct?

I'm sorry, but a quick check of the graphs would suggest otherwise.

Please reply showing all of your steps and reasoning. Thank you.

Eliz.