Calc BC Exam Question

  • Thread starter hamburgler
  • Start date
  • #1
22
0
I'm doing a calc BC practice exam and I found this question that stumps me to the max:

The function y=x^4+bx^2+8x+1 has a horizontal tangent and a point of inflection for the same value of x. What must be the value of b?


I know that points of inflection are found from the second derivative and setting that function to zero, however the 'b' value really throws me off :yuck:

Oh btw here are the mc answers.

a) -6 b)-1 c) 1 d) 4 e) 6
 

Answers and Replies

  • #2
lurflurf
Homework Helper
2,440
138
under what conditions does the function have a hotizontal tangent
Under what conditions does the function have a point of inflection
once you know that it should be easy to see when both occur
you will also see what b must be
 

Related Threads on Calc BC Exam Question

  • Last Post
Replies
1
Views
2K
Replies
3
Views
10K
  • Last Post
Replies
5
Views
2K
  • Last Post
Replies
21
Views
4K
  • Last Post
Replies
6
Views
1K
Replies
1
Views
2K
  • Last Post
Replies
0
Views
979
  • Last Post
Replies
4
Views
2K
  • Last Post
Replies
4
Views
2K
Top