calc help pleeeeeeeeeeeeease

[Solver]

Ah, right, you have a system where some HS courses are optional already. Good

[Dry]

I'd try either pythagoras or the trigonometric cercle... not sure...
So, either:
y = sqrt(64 - x^2)
or
x/2 = 4 * sin
y/2 = 4 * cos

I have a better feeling with the first one...

However, the area of the rectangle is 4 * radius * sin *cos, which sounds like a cool function.

[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.

[Kuciwalker]

Originally posted by Solver
WTF is A(x)? Never seen similar notation.

It's fairly common over here; at least, I've rarely seen different.

[Solver]

Originally posted by Kuciwalker


It's fairly common over here; at least, I've rarely seen different.

So what is its use? For a function that you have to find yourself?

[Kuciwalker]

They're just saying "find the area of the rectangle as a function of x, and denote this function with A(x)".

[Solver]

I figured as much. What bugs me is why it's A(x) and not F(x).

[Kuciwalker]

Why?

[Solver]

F(x) is the standard notation for a function, unless it's somehow special... no reason to deviate

[Kuciwalker]

f(x) is the standard notation for an arbitrary function. This is a fixed function with actual semantics, thus it gets a letter that indicates those semantics.

[Kidlicious]

[Solver]

Oh. A = Area.

[Locutus]

Originally posted by Solver
WTF is A(x)? Never seen similar notation.

A(rea) as a function of x, only the most common notation in the world. What the hell kind of calc do they teach you in Latvia?

You consider derivatives advanced for a 16-year-old? That's retardedly basic (for polynomials anyway), we do those at age 11-12 over here (on the highest level of the education pyramid, wouldn't know about lower levels).

Kuci's tips should help you, b etor, although it seems you already got the gist of it yourself with the first one. The rest follows from that.

[Solver]

Yeah, took me a while to realize it's A for area. I'm used to area functions being S.

It's not that I consider derivatives to be advanced... they're simple to do. It's that I am surprised every time I get reminded that calculus is taught at school level in other countries. Here you don't get any calculus at all in school anymore.

[b etor]

Originally posted by Kuciwalker
A. You have a right triangle with sides length x and y and hypotenuse length 8. Apply the Pythagorean theorem, then some algebra and you have y in terms of x.

B. A(x) = x * y. Since you already know y in terms of x, substitute that and you have A(x) = x * f(x).

C. Just figure out what values of x are possible given the geometry. Clearly x can't be less than zero, and the upper bound is equally obvious.

D. Easy once you have A(x).

E. ... it's kinda obvious I can't help you here.

thankyou

Originally posted by Solver
Calculus at 16? Then again, it's not really calc...

there's a guy in my class that's 15.
this is real calc, it's just the first semester. we have to take the AP AB&BC exams at the end of the year.