"Degrees of freedom" for lines
I'm reading something about "degrees of freedom" trying to learn what exactly it means, and there's this one sentence I'm running into that I can't really understand...
What is this "the two independent ratios {a : b : c}" ?
They talk a lot about how a line on...
I don't get it. Are you saying that because x is the upper bound of the summation that means it's limited to nonnegative integers and because of that, you can't take the derivative?
How's it not a variable? I looked up the definition on Mathworld.com:
and x can take on different values...
Hey I was doing a standard derivative problem but I ran into something somewhat strange. Check it out:
\frac{d}{dx}\sum_{i=1}^xx=\frac{d}{dx}x^2=2x
Okay, simple enough..but what if I write it like this?
\frac{d}{dx}\sum_{i=1}^xx=\frac{d}{dx}(x+x+...+x)=1+1+...+1=x.
Why am I getting two...
Thanks everyone I've read what you've all written and I understand this triangle thing now but I still don't understand work at all.
I'm really confused on this: Say there's a box of mass m on the ground. I pick it up to my chest (h meters) and so have done mgh joules of work on the box. Now...
But why is the force equal to mg\sin(\theta)? Are you only considering the horizontal component of the force? (If so, why?) And is that 'd' you wrote just a general d or does it refer specifically to the d I drew in the picture (the length of the ramp)?
Equal work lifting versus pushing up a plane??
I don't understand anything in physics having to do with work and/or energy. I drew a picture of the problem I'm having now:
http://img80.imageshack.us/img80/9834/physicsoc8.png
According to every physics book/website ever, the work in...
[SIZE="4"]THE PROBLEM: (my own words) For a rotating circle with radius 2.10cm, the centripetal acceleration on the rim must be 100g. In revolutions per minute, what is the rate of rotation required?
[SIZE="4"]MY SOLUTION:
1. Centripetal acceleration is given by a_c = \frac{v^2}{r} and so...
gabee that's kind of a cool strategy. I'll try and keep that one in mind.
gerben I'm not seeing the last part of your post (add either to get 90). Do you mean add theta to the outer red angle or add alpha to the inner red angle? I don't see how you get 90.
Here's the free-body diagram of a stupid physics problem I had:
http://img211.imageshack.us/img211/5081/triangleey9.png
When going over this problem both my book and my lecturer say that \alpha = \theta (they actually don't even mention \alpha; they just write it as \theta to begin with. I...
This isn't a homework problem but I found it on the internet and can't figure out how to do it. It's one of those "divisible by whatever"-type problems which I never learned how to solve...
I don't know how to work with this divisibility stuff when it's generalized to numbers like x+y+z. I...
The problem is to find h on this triangle:
http://img215.imageshack.us/img215/7006/triangleum3.png
With the help of the law of sines I've already finished this problem. But I tried doing it a different way and my new solution isn't working and I can't figure out why. Here's what I did...