# Thread: Need help with science/math schoolwork? Post here!

1. ## Re: Need help with science/math schoolwork? Post here!

Blue is the normal force. You would also have friction when it moves.

2. ## Re: Need help with science/math schoolwork? Post here!

RC-association or RC-model in statistics, what is it really? Does anyone know?

3. ## Re: Need help with science/math schoolwork? Post here!

Doing exponents and exponential factors right now.

My homework it tells me to graph:
f(x) = 4(1/2)^x

I don't know how to graph it so any help would be nice.

Also Reasoning Is y = (-2)^x an exponential function? Justify your answer.
Hope I can get some help

4. ## Re: Need help with science/math schoolwork? Post here!

First put in

x = 0

And

x = infinity

Then connect with a curved line.

5. ## Re: Need help with science/math schoolwork? Post here!

Originally Posted by Sphere
First put in

x = 0

And

x = infinity

Then connect with a curved line.
How the foo do you graph infinite o;

6. ## Re: Need help with science/math schoolwork? Post here!

How the foo do you graph infinite o;
Very carefully.

But my point was figure out where the graph ends up with very large values of x, does it level off at some point?, does it become negative? Does it become zero? You probably haven't been exposed to limits yet so don't bother thinking about infinity, just think about how the graph goes with big values of x.

7. ## Re: Need help with science/math schoolwork? Post here!

Originally Posted by Sphere
Very carefully.

But my point was figure out where the graph ends up with very large values of x, does it level off at some point?, does it become negative? Does it become zero? You probably haven't been exposed to limits yet so don't bother thinking about infinity, just think about how the graph goes with big values of x.
Okay thanks :]. We had the big test yesterday and I got 34/35 right with no extra credit ( I didn't wanna do it . )

Thanks for all the help.

8. ## Re: Need help with science/math schoolwork? Post here!

Does TWC support Latex? That would be nice.
a,b,c are non-negative real numbers, a+b+c=2
Prove that (a^2+b^2)(b^2+c^2)(c^2+a^2)<= 2

9. ## Re: Need help with science/math schoolwork? Post here!

Looks like a triangle inequality problem, but the solution is eluding me. Perhaps you could give some more info about the class this is for? Algebra? Pre-Calc? Calculus? What properties of reals, particularly inequalities, have you been studying?

10. ## Re: Need help with science/math schoolwork? Post here!

Originally Posted by chriscase
Looks like a triangle inequality problem, but the solution is eluding me. Perhaps you could give some more info about the class this is for? Algebra? Pre-Calc? Calculus? What properties of reals, particularly inequalities, have you been studying?
Algebra. And it's not a triangle inequality.

11. Ok. So have you solved it?

12. ## Re: Need help with science/math schoolwork? Post here!

Originally Posted by chriscase
Ok. So have you solved it?
No

I have another one if you're interested in.
a,b,c range in [1;4] ; a+b+c =8
Prove that a^2 + b^2 + c^2 <= 26

13. ## Re: Need help with science/math schoolwork? Post here!

I have another one if you're interested in.
a,b,c range in [1;4] ; a+b+c =8
Prove that a^2 + b^2 + c^2 <= 26
You might want to be more specific about your range, else that is a false statement. (e.g. 4, 3.9, .1)

14. ## Re: Need help with science/math schoolwork? Post here!

Originally Posted by Sphere
You might want to be more specific about your range, else that is a false statement. (e.g. 4, 3.9, .1)
err... all 3 numbers are locked in [1;4] ; your example has a number out of the range (0.1).
------------
After making some efforts I think I've made it even a harder problem
a,b,c ranges in [1;4], so:

So we have to prove:

Which is literally, in 3 numbers there must be a number which ranges in [2;3].
It's a harder problem for me

16. ## Re: Need help with science/math schoolwork? Post here!

Originally Posted by Sphere
I think the interval notation usually goes more like [a,b]. [a;b] looks odd to me, but I assumed it was a closed real interval.

I am somewhat suspicious of these problems now. If they are something provided by a student, it's possible they are nothing more than a graphing calculator exercise. When a problem like this is assigned in a class there is usually a substitution or other trick that solves it handily.

17. ## Re: Need help with science/math schoolwork? Post here!

Originally Posted by chriscase
I think the interval notation usually goes more like [a,b]. [a;b] looks odd to me, but I assumed it was a closed real interval.

I am somewhat suspicious of these problems now. If they are something provided by a student, it's possible they are nothing more than a graphing calculator exercise. When a problem like this is assigned in a class there is usually a substitution or other trick that solves it handily.
I'm sorry.
In my country it's usually [a;b] instead of [a,b] because "1,3" can be a number. (I know you guys use "1.3" for "one point three").
I'm sorry for any misunderstanding. This is my homework by my teacher.

I'm in grade 10 and I haven't seen any inequalities solved by using graphs in my grade.

----
Edit:
"in 3 numbers there must be a number which ranges in [2;3]"
This is wrong. for (3.5;3.5;1), there's no number in [2;3] but still in [1;4] and sum = 8

18. ## Re: Need help with science/math schoolwork? Post here!

Originally Posted by lmt96
Does TWC support Latex? That would be nice.
a,b,c are non-negative real numbers, a+b+c=2
Prove that (a^2+b^2)(b^2+c^2)(c^2+a^2)<= 2
Chriscase is right, this is a geometry problem,

they give you 2 shapes:
S1: x+y+z=2
S2: (x^2+y^2)(y^2+z^2)(z^2+x^2) = 2

and by putting the <= you have to prove that when S2 partition the space, S1 is entirely on the right side (aka S1 does not cross S2, but can be tangent in this case)

Butif M(x,y,z) belongs to S1, in this case it can be on either side of S2, so it's impossible to prove it

M(0,0,2) belong to S1 you have 0<=2 and for M(-10,10,2) belong to S1 you don't have 200*104*104 <=2 .

Those problem are usually designed as have one equation really easy to recognaize but not the other. Your job is to make geographic sense of the equation (usually changing x,y,z by their cylindric or spheric coordonates does the trick).

19. ## Re: Need help with science/math schoolwork? Post here!

Uhh....could someone help me (ie tell me the answer) with this (easy?) equation?

(-7s-6t)/3 = (-s-3u)/-2

Thanks.

20. ## Re: Need help with science/math schoolwork? Post here!

One equation, three unknowns. What exactly are we supposed to do, call Jesus?