Recent content by FsLiu

Hey guys, I'm contemplating doing a Master's degree in materials engineering. I'm graduating with a petroleum engineering degree in the spring of next year. I've had numerous internships which, after some weeks of reflection, made me realize that I'm simply not happy when I'm working for...

It may not suffice, but what is true, assuming g(x)=7x3/3, is g'(0)=g''(0)=0 and g'''(0)=14. And the question asks for the value of f'(0), so any possible equation of g(x) would suffice. Thanks for all the input guys, but I'm going conclude that question there and ask the TA's/profs about...

Wait but the original question stated that g(0)=g'(0)=g''(0)=0, sorry I forgot to edit that in. I asked a second year student about it though, and he thinks it'd suffice because I found one general solution to the problem, and the question is only asking for f'(0) which I found to be 7/3.

ahh, now I'm confused as f**, what did I do wrong in the integrals? Also, the counterexample you gave does yield the same answer to f'(0)=7/3, and just out of curiosity, how did you come up with that counterexample so quickly, I'm quite baffled, are you a mathematician or prof or something?

Wait, but g'''(0)=14 integrate that, g''(x)=14x+C, C=0 since g''(0)=0 through substitution integrate, g'(x)=7x2+C, again C=0 through substitution integrate, g(x)=7x3/3+C, C=0 through substitution then plug that g(x) into the piecewise function to get f(x)=7x/3 Seems to work, doesn't it?

Yeah, forgot to mention that sorry. I actually took a different approach to the question while I was thinking about it in class. I figured that using L'Hopital's rule multiple times only seems to prove that the function is continuous. I integrated g'''(x) multiple times to get an equation...

Homework Statement Find f'(0) given a piecewise function defined as f(x) = {g(x)/x2, x≠0 {0, x=0 where g(x) is a function satisfying g(0)=g'(0)=g''(0) and g'''(0)=14 Homework Equations none. The Attempt at a Solution So far, I've reasoned that for f to be differentiable...

Yeah that's the problem, doesn't make sense logically/physically. I used the equation x = A cos(wt-phi), assumed phi was zero and rearranged for time, t. Then I did t1 at -0.05m and t2 at +0.05m and then took the difference as the time taken to go from point one to point 2.

Those are both given in the original question, A=0.100m and w=2pi(period inverse) which turns out to be 1.48 Hz

Homework Statement Homework Equations x = A cos(wt-phi) The Attempt at a Solution Using the above equation for t, calculating values for t1 at -0.05 and t2 at 0.05, as well as assuming phase angle phi is zero, I get an answer of over 40 seconds. I think I may be using the wrong equation or...

Yeah my brain doesn't work it seems Thanks.

I'm sorry for the ingratitude, but physics is killing me since I'm 2 weeks behind as the professor does nothing but write formulas on the board and I understand none of it so I've been teaching myself. In addition, I have 4 other courses equally as difficult, though I'm not behind in them...

pi(r^2), the area for a circle. Please just give me a better hint or walk me through how to do it. I honestly have no time for your playing around with me like this with another 4 classes on my hands.

So what you're saying is, I should do pi(4.1^2)? edit: still doesn't work and I lost another 5% on the assignment. edit2: still not getting it, but I have a feeling a sphere has something to do with it?

Alright, I'll just restate again that what I thought to be correct was Intensity*Distance^2 gives watts, and the energy in one hour is watts*3600s Can you just tell me why this is wrong?