purplegrl28

The equation is...

A(w,p,q) = 1/sqr((q-w^2)^2 + p^2*w^2)

And the question is...

What is dA/dw?

And a follow up question is...

Fix p and q, and let M(p,q) denote the maximum value of A(w,p,q) as a function of w. Compute an expression for M(p,q).

...for this, I figure you would set the partial derivative to zero and solve it, but I'm not getting the answer that's in my textbook. Any help is appreciated!

Find the general solution of:

y'' + 4y' + 20y = e^(-2t)sin(4t)

I know the characteristic equation is y^2 + 4y + 20 = 0, which has roots -2+4i and -2 - 4i. This means the solution to the homogeneous equation is

y = e^(-2t)*(Acos(4t) + Bsin(4t))

I don't know what to do with the e^(-2t)sin(4t) on the right hand side of the given equation. I think you use the method of undetermined coefficients, but I don't know what would work.

Any help is appreciated!

Find the general solution of...

y''' - 3y'' + 2y' = t + e^t

The main part I'm having trouble with is doing the method of undetermined coefficients for the right hand side of the equation. Any help is appreciated.

Once again, the system is...

dx/dt = 2y

dy/dt = 0

In matrix form, it would be dY = [[0 2],[0,0]]Y

I feel like this one should be easy, but I don't get it. Can someone help me find the general solution?

The problem is:

dy/dt = t/t^2y + y, which I separated into

dy/dt = (t/(t^2 + 1))(1/y)

Then you get

int(ydy) = int(t/(t^2 + 1)dt)

Anyway, I solved it and ended up getting

y = +- sqrt(ln(t^2 + 1) + C)

but my book says the answer is

y = +- sqrt(ln(C(t^2 + 1))

Why is the constant in front of the part in parentheses? Is there a property of exponentials or logarithms that I'm missing?

I'm pretty flat chested, and I wish I had something to show off...so I'm asking all the girls who actually do, why do you like to show it off? Would you still have reservations about actually showing a guy your boobs, even a bf?

No need to point out that I'm jealous, that's pretty obvious...I'm not trying to hate, power to you if you got 'em...I'm just looking for some perspective.

I met this great guy when I went away to college. He was and is still taken. His gf goes to another college. Anyway, this guy and I have a lot in common, and we click really well. I knew 1st semester that it would be dangerous to let myself get too close to him because I knew from the start that I couldn't have him. He kept talking to me nonstop, and we kept hanging out (purely as friends, no kissing/hooking up or anything, just hugs), but it started bugging me how great of friends we were when he had a gf. He also never talks to me about her or his relationship, so I started thinking maybe he'd rather be with me. He's a really good guy, and he'd never cheat or be disloyal, but I'm not unattractive, so I thought maybe he liked me at least a little bit. I decided to tell him how I had been feeling, and it blew up in my face. He said he has a habit of getting too close to girls who are intended to just be friends, and I had suspected this because he is really extroverted. He also said he likes to keep his relationship to himself because it's no one else's business, which makes no sense to me. If I'm really his best friend, and he really loves this girl, why not tell me more about her? Anyway, I thought it was weird that he needed this close friendship with me when he has a gf. Is it normal for guys to be this way? He really is a great friend, and he's willing to stay friends even though he knows I really want something more. I just don't understand why he needed to befriend me like this in the first place...I thought friend-zoning was something girls did to guys and not the other way around.

I would appreciate any insight, especially from guys. :)

So I liked this guy, and he didn't want to go with me, so now I'm not going. People tell me that not going is letting him win. Yes I am heartbroken, but I don't think going with friends is any fun. Prom has no novelty that way. It's only fun with a date. Opinions?

I'm a runner, and I never get calf cramps when I am training in season, but when I go to take a couple weeks off in between seasons, I get excruciating pain in my calf muscle at night. It's only at night and only when I am not training. Has anyone else experienced this or have any insight?

I can't tell if it's because we look hot, or they are making fun of us...or maybe they are just pervs. A little insight please?

Girls pretty much always do, and in my opinion it's nasty not to, so I was just wondering about guys.

I'm doing a psychology project, and I need college students to give me their combined SAT score (for all 3 sections) and their current college GPA. I'm trying to see how well SAT scores correlate to GPA in college. I think this is the third time I've asked, but I really need some data and no one's responding. It's a simple question!!

I am doing a brief study for my psychology class about how well the SAT predicts how a person will do in college. So, if you are in college and could help me out by giving me some data, that would be great! :)

I need SAT scores from high school, and current GPA.

I tried using malwarebytes, and I also ran my Norton Internet Security scanner. I thought that Antivirus 2009 was gone. However, I am still getting the pop-ups saying that my computer has viruses and needs to be scanned. Other than the pop-ups, the program seems to be gone. It is not in my programs list, and it is not in my task bar anymore. The program is obviously not gone though, as I am still getting pop-ups.

There's a group on facebook that allows users to find out who's looked on their profile. My question is does it work, and does it show the history of who's looked at your profile from even before you joined the group? I am soooo screwed because I've looked at my crush's profile like every day...and he just joined that group. CRAP!

(x+1)^3(4x-9) - (16x+9)(x+1)^2

Is there any shorter way to do it besides multiplying it all out and re-factoring? If not, I would greatly appreciate it if someone could just do this problem so I have an example to follow. I don't need explanation; I just need to see the work laid out.

Thanks in advance. :)

People are usually more open to conversation online if they are shy in person, but is there such a thing as still being shy to start a conversation on the internet?

I just found out about "69" last week. (Someone told me.) Well, anyway, I had NO idea that a number could refer to something sexual, so I was just wondering if there's anyone else who either doesn't know what 69 means or prefers to have numbers just be numbers.

This is supposed to be an acid/base reaction, but it's not a typical one because the typical ones usually end up with a salt and water, but there's no oxygen in those reactants, so water can't be a product. What are the products for this reaction?

I know that there are 6.02 x 10^23 atoms in one mole of carbon dioxide, but I don't know. I'm just really confused right now. I've been working on my chemistry summer packet all day...