# Thread: any examples to show d2y/dx2 of max/min point can be 0

1. ## any examples to show d2y/dx2 of max/min point can be 0

Any good examples showing $\displaystyle {d2y}/{dx2}$of max/min point can be 0?

Thanks.

2. y = ax +b

Try this one.

3. Originally Posted by sa-ri-ga-ma
y = ax +b

Try this one.
the qn is max or min point, not straight line.

4. Originally Posted by stupidguy
Any good examples showing $\displaystyle {d2y}/{dx2}$of max/min point can be 0?

Thanks.
y = x^(2n) where n > 1.

5. Originally Posted by mr fantastic
y = x^(2n) where n > 1.
Can I show the 3 graphs in LATEX?

6. Hello, stupidguy!

$\displaystyle \text{Any good examples showing }\frac{d^2y}{dx^2}\text{ of max/min point can be 0?}$

mr fantstic nailed it!

$\displaystyle y \:=\:x^4$ is shaped like a parabola, but rises more steeply
. . and is "fatter" near the origin.

Code:
              |
*           |           *
|
|
*          |          *
|
*         |         *
*        |        *
*      |      *
*   |   *
- - - - - - - * - - - - - - -
|

There is a minimum at (0,0).

The concavity is 0 because the curve "flattens" slightly there.

7. Here's another:
$\displaystyle y = \frac x 2 - \frac {sin 2 x} 4$

You get
$\displaystyle y' = sin^2 x$
$\displaystyle y'' = 2 sinx\ cosx$

8. how did you plot a graph? did you use latex?

9. Originally Posted by stupidguy
how did you plot a graph? did you use latex?
Maybe there's an easier way, but what I do is make the graph in Excel, then take a screen shot of the graph, save it as a jpg, then use the Attachments tool under "Go Advanced."

10. Originally Posted by ebaines
Maybe there's an easier way, but what I do is make the graph in Excel, then take a screen shot of the graph, save it as a jpg, then use the AtTtachments tool under "Go Advanced.
I am so touched that you did so much to explain to me without any return.