calc help pleeeeeeeeeeeeease

[Solver]

Originally posted by snoopy369


If Kuci's right, which I have no reason to believe he's wrong, the issue is that this isn't really geometry; it's a theoretical function problem. If this were engineering then clearly the range would be different (as 0 would be illegal); but it's not Get used to theoretical math allowing anything that is allowed under the rules of math, not just the rules of reality

That depends on how the task is defined. If A is a function of a rectangle's area, then one would assume 0 is not a legal result if the rectangle is supposed to exist. Without seeing a more exact definition of the task, it seems to be a geometry problem, not function theory...

[Kuciwalker]

snoopy: if zero area is illegal, it should be ( ), not ( ]. x = 8 also gives zero area.

[Kuciwalker]

Originally posted by Solver
That depends on how the task is defined. If A is a function of a rectangle's area, then one would assume 0 is not a legal result if the rectangle is supposed to exist. Without seeing a more exact definition of the task, it seems to be a geometry problem, not function theory...

A rectangle of area zero can still exist just fine...

[Solver]

A rectangle of area zero can still exist just fine...

With a non-zero diagonal?

[Kuciwalker]

Sure, why not? I mean, you can define a rectangle to have nonzero area, but I don't see much advantage to such a definition.

[snoopy369]

Originally posted by Kuciwalker
snoopy: if zero area is illegal, it should be ( ), not ( ]. x = 8 also gives zero area.

Yeah, didn't really think that one through too much

[b etor]

Originally posted by Kidicious


I'm sure she will get beat up by the other students for that.

the other students live all over the place. there are like 15 of us and 3 live in california, so i think i'd be alright. anyway, we go at our own pace. i just started a few weeks late because my school took a while to get me registered for the class.

[b etor]

thanks, guys. i'll be posting in this thread again.

[Kidlicious]

Originally posted by b etor


the other students live all over the place. there are like 15 of us and 3 live in california, so i think i'd be alright. anyway, we go at our own pace. i just started a few weeks late because my school took a while to get me registered for the class.

Oh right it's an online class.

[Blake]

Originally posted by Zkribbler
I can't help you.
Althoough I received the award for being the top math & science student in my high school, I got thru calc by memorizing the formulas and mechanically applying them. I had no idea what I was doing.

lol, me too.

Most memorable was that I got top of the electronics class, and couldn't reliably wire simple circuits, to the point of getting the black and red wires confused, LOL.
But I could sure work with formulas!

But I was also pretty good at actually deriving stuff from first principles (that was my modus operandi)... but only in the domain of mathematics, no practical real-world skill whatever.

[-Jrabbit]

...no practical real-world skill whatever.

Sounds like a perfect background for programming AIs...

[Victor Galis]

Originally posted by b etor
ok so for B. i put A(x) = sqrt(64-x²) * x which i'm assuming is correct.
so for C. can i just put that x is less than 8 and greater than 0? or is there a formula i need to use? cuz it looks like it's around four but i can't prove that.

For B, remember that's the area of a square with those sides, triangles are half as big.

Yep, but the functions are all still well-defined there and have a meaningful geometric interpretation (triangle of area zero).

Except a triangle with area zero isn't a triangle. Isn't there some sort of theorem that says something like: The sum of the lengths of the two shorter sides of a triangle is greater than the length of the longest side. Neither 0 or 8 can be in the domain for this to actually be a triangle.

[b etor]

rectangle. but yea.

[Zkribbler]

Originally posted by b etor
rectangle. but yea.

A square is just a rectangle that lacks imagination.

[Kuciwalker]

VG, she was supposed to find the area of the rectangle, not the triangle. And re: definition of a triangle, it's inherently an edge case and the definition is equally useful either way. There's no particular reason to exclude zero-area triangles.