Question

For what values of x is the graph of y= (-3)/4+x concave downward?

Answer 1

@AnswerMyQuestions @CausticSyndicalist @iGreen @JFraser @YanaSidlinskiy

Answer 2

@mathmate Please help! :)

Answer 3

do you mean to have
\(y= \dfrac{-3}{4+x}\)

Answer 4

yes

Answer 5

I think I may have figured it out

Answer 6

Do you still recall when is a graph concave downwards?

Answer 7

Can I run it by you?

Answer 8

Remember: definitions solve a lot of problems!

Answer 9

Definnitely!

Answer 10

Concave up is the shape of a cup, and concave down looks like a dome

Answer 11

soo x>-4

Answer 12

Yes, the answer is correct, but it's like the computer graphing is cheating for you! lol
You have not yet applied what you learned:
Concave down is when f"(x)<0.
Can you work from that?

Answer 13

I don't understand what you mean?

Answer 14

work from that?

Answer 15

Do you agree that it's concave down when f"(x)<0 ?
If you do, then we can find f"(x) and determine what values of x will make f"(x)<0.

Answer 16

Yes i do.

Answer 17

so find the second derivative?

Answer 18

Yes, please post it when you've got it.