What is the difference between local max and absolute max ? sketch the graph. a. the domain (-4,6) b. absolute maximum of 6 at x=0 c. local maximum of 0 at x=-2 d. no absolute minimum e. it is CU...

What is the difference between local max and absolute max ?

sketch the graph.

a. the domain (-4,6)

b. absolute maximum of 6 at x=0

c. local maximum of 0 at x=-2

d. no absolute minimum

e. it is CU on the interval (0,6)

Asked on by bdremm

1 Answer | Add Yours

mlehuzzah's profile pic

mlehuzzah | Student, Graduate | (Level 1) Associate Educator

Posted on

The domain is (-4,6); so we don't want to draw anything outside that interval, and we don't want any "holes" in that interval.  (every point in that interval needs a corresponding point in the graph)

 

absolute max at (0,6)

 

So we want to keep the graph inside the dotted lines, and go through that point (0,6)

local max at (-2,0) means all the points "near -2" are less than 0, so we need something like this in the graph:

we want to have no absolute minimum.  The way to do this is to have the graph head down to `- oo` .  That way the points get smaller and smaller, but none of them is the smallest, because none of them is actually `-oo` .

So:

 

Note: our graph doesn't actually have to be continuous, it is just that every point in the horizontal interval (-4,6) needs to have a corresponding y value (dot on the graph).

(by the way, the function I used to get that was  `-((x+2)^2)/(x+4)`    ) 

 

Now, we need to make it concave up from (0,6), but we need to be decreasing (or else 0 won't be an absolute max):

 

Note: there is an open dot at 6, because we want the domain to be (-4,6) and not (-4,6] (that is, we don't want 6 to have a spot on the graph, just everything up to 6.

Also: the function I used for the second part of the graph was: `-(x-6)^2/6`  ` `

 

 

Finally, the difference between an absolute maximum and a local maximum:

an absolute max is greater than or equal to everything else.  That point at (0,6) is the highest thing on the graph.  a local max might also be an absolute max, but it doesn't have to be.  It just has to be larger than the stuff nearby.  0 is not the tallest point on the graph.  But every x value "near" -2, is less than 0. 

We’ve answered 318,991 questions. We can answer yours, too.

Ask a question