Recent content by becca4

Gotcha.

It worked! Thanks much! Now with the initial values: I have my general solution y = c1*exp(-2x) + c2*exp(x) -x -1/2 All I'll do to find c1 and c2 is use y(0)=0 in that equation, then take its derivative and use the y'(0)=1, that's the way to go, correct?

Ahhh... Clever.

Edit: general solution y = yc + yp. Does that help? My strategy is to find the yc part of the general y solution, pretending like the left side of the original eqn is equal to zero. Then to find yp I'm supposed to make a reasonable assumption to find it. All parts of yc and yp must be linearly...

Homework Statement Find solution for y'' + y' -2y = 2x with initial values of y(0) = 0, y'(0) = 1 Homework Equations I have found yc = c1*exp(-2x) + c2*exp(x), but finding yp is what I'm having trouble with... AND THEN I'm not so sure how to go about the initial value. The Attempt at...

the latter. Thanks!

Homework Statement See picture It's (sigma) from k (possibly n?)=1 to +infinity of U_{k} = 2 - (1/n) I'm asked to find: U_{100} limit as k goes to infinity of U_{k} and sigma from k=1 to inf. of U_{k} Homework Equations If I'm not mistaken, 2 - 1/n is the closed for for...

I agree. I have the hp 50g and am very happy with it, once I went rpn, I never went back. Well, I did at times when the 50g's symbolic solving didn't sit so well with the professors, but honestly, it's one of the best investments I've ever made. I'd recommend it for people going into engineering.

So I am on the right track?

Ok, yeah, that makes sense. So now, k - ( e^k (1-k) ) / d/dk ( e^k (1-k) ) should give me what k converges to, meaning the value of k that when 1/2 is subtracted, equals to zero, right?? So for 2/3, I'd use this equation to solve for k using Newton's method, e^k (1-k)= 2/3...

I copied the problem verbatim from the handout I was given, so I'm sorry that it doesn't make a whole lot of sense to you... Yes, I mean to say that the line y = k splits the area in half. And yes, I know how to integrate ln(x), but it doesn't do me a whole lot if I don't know what I'm doing...

Homework Statement Problem: A (area) = \int^{e}_{1} ln(x) dx = 1 Now we let k be such that 0 \leq k \leq1 Consider the line y = k. Find k so that area computed by A is exactly one half. Homework Equations So, first, I found point of intersection: k = ln (x) e^{k} = x...

Ok, sorry to bring this up again. Talking to some of my classmates, some of them think that this is supposed to be a proof using Taylor series stuff, and that at the end that's where the -2 comes from. Any thoughts on that?

I think I almost have it. The only thing that I'm still wondering is about the relation part, what does the minus sign mean?

I still don't really understand...