Question

Below is the graph of f ′(x), the derivative of f(x), and has x-intercepts at x = –3, x = 1 and x = 2. There are horizontal tangents at x = –1.5 and x = 1.5. Which of the following statements is true?

Answer 1

https://i.gyazo.com/f475d14cb58c410d88e94c4bef8cdb8d.png
@jim_thompson5910 can you check for me?

Answer 2

go back to the previous problem. You did the first derivative test when you checked to see the sign changes in f ' (x) as it passed through x = 5

Answer 3

for this graph f ' (x) is positive when we're to the left of x = 1

f ' (x) is negative when we're to the right of x = 1

Answer 4

I get it but wouldn't the top of the curve represent a horizontal line?

Answer 5

Slope at that point is 0