What is 2015: Definition and 219 Discussions

2015 (MMXV) was a common year starting on Thursday of the Gregorian calendar, the 2015th year of the Common Era (CE) and Anno Domini (AD) designations, the 15th year of the 3rd millennium, the 15th year of the 21st century, and the 6th year of the 2010s decade.
2015 was designated by the United Nations as:

International Year of Light
International Year of Soil

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  1. Jameson

    MHB What courses are you taking, Spring 2015 edition

    Now that the new year has begun, I am excited to see more people popping in with their questions. If you are a student or teacher, what classes will you be involved in this semester? I am a current graduate student of statistics, taking 3 courses. Non-parametric modeling, applied matrix...
  2. Euge

    MHB Solution: Proving $f$ is identically zero

    Here's this week's problem! __________ Problem. Let $f : \Bbb R \to \Bbb C$ be a continuously differentiable, 1-periodic function such that and $f(x/2) + f((x+1)/2) = f(x)$, for all $x\in \Bbb R$. Prove that $f$ is identically zero. __________ Remember to read the...
  3. Ackbach

    MHB What is the voltage across the resistor in this AC circuit problem?

    Here is this week's University POTW. ----- Refer to the following figure: https://www.physicsforums.com/attachments/3820._xfImport Given that $R1=1\times 10^6 \, \Omega$, $C1=1\times 10^{-9} \, \text{F}$, and $L1=1\times 10^{-3}\,\text{H}$, and that $V1(t)=120 \cos(120 \pi t)\,\text{V}$...
  4. anemone

    MHB What Happens to the Limit of a Function as x Approaches Zero?

    Evaluate $\displaystyle \lim_{{x}\to{0}}\dfrac{P(x^2)-P(x)}{P(x)-P(0)}$ if $P(x)$ is a strictly increasing and differentiable function with $P(0)=0$. Remember to read the http://www.mathhelpboards.com/showthread.php?772-Problem-of-the-Week-%28POTW%29-Procedure-and-Guidelines to find out how to...
  5. marcus

    Six themes for QG in 2015 (developments to watch for)

    Not in any particular order (all are active important research initiatives). 1. Algebraic geomatter (google "geometry and the quantum: basics") 2. LQG with constant curvature simplices (embodying the cosmological curvature constant Λ) 3. Flux formulation LQG 4. LambdaCDM bounce 5. Projective...
  6. davenn

    First seismic T-Phase events for 2015

    hi everyone, Well we are into a new year and into new discoveries and observations Yesterday morning, Jan 6th, 0548NZST ( 05 Jan 1748UT) there was a reasonable quake in the mountains of the central South Island of New Zealand M 6.0 GNZ ( M 5.6 USGS). Now the quake itself isn't unusual, NZ is...
  7. Dishsoap

    2015 Summer Internships Thread

    I posted one of these threads for the 2014 summer internships. Please post what you apply for and don't forget to update it when you've heard back! REU at CERN (I figure my chances of getting in are even lower if I don't apply!) University of Michigan REU University of Colorado - Boulder REU...
  8. Ackbach

    MHB Who Solved the Crime in the Latest Problem of the Week?

    Here is this week's University POTW. ----- Four suspects of a crime made the following statements to the police: Andy: Carl did it. Bob: I did not do it. Carl: Dave did it. Dave: Carl lied when he said I did it. Given that one of them "did it" and that exactly one of them told the truth, who...
  9. Euge

    MHB How can we prove that if a sequence is decreasing and has a sum of infinity, then the limit of n times the nth term of the sequence is zero?"

    Here is the first problem for 2015! ______________ Show that if $(a_n)$ is a decreasing sequence of positive real numbers such that $\sum_{n = 1}^\infty a_n$ converges, then $\lim_{n\to \infty} na_n = 0$. As a consequence, prove that the series $\sum_{n = 1}^\infty (n^{1/n} - 1)$ diverges...
  10. anemone

    MHB What is the ordered pair (x,y) for the given equation?

    If $x$ and $y$ are positive integers such that $\sqrt{8+\sqrt{{32}+\sqrt{768}}}=x\cos \dfrac{\pi}{y}$, compute the ordered pair $(x,\,y)$. Remember to read the http://www.mathhelpboards.com/showthread.php?772-Problem-of-the-Week-%28POTW%29-Procedure-and-Guidelines to find out how to...
  11. A

    SULI Summer 2015: Selection Process & Application Q&A

    Does anyone know how SULI's selection process works? On the application you list your top two choices for labs; does your application get sent to those two labs for the mentors to pick or is there some sort of prescreening by the DOE? Thanks.
  12. anemone

    MHB Evaluating $a^2+ab+b^2=0$: A 2015 Challenge

    If $a,\,b$ are non-zero numbers with $a^2+ab+b^2=0$. Evaluate $\left(\dfrac{a}{a+b}\right)^{2015}+\left(\dfrac{b}{a+b}\right)^{2015}$.
  13. P

    Is Now the Best Time to Study String Theory?

    Hello Everyone, I want to know if it's a good time to study string theory from the basics? Or is it wiser to wait till next year, after the 2015 LHC run, if indeed we find any evidence for it? I have done a course in mathematical physics, classical and quantum field theory, electrodynamics and...
  14. D

    Summer Internships Europe 2015

    I am currently an undergraduate at a small physics school in Texas. I'm a freshman, but I'll be graduating in ~2.5-3 years (lots of ap credits/local uni). My parents are in the process of moving to Europe(Italy), and I really would like to find something physics related I could do for the...
  15. A

    Path to follow to learn maths and physics this year before school (sept 2015)

    Hey guys, I am a software developer who plans to go back to school in September 2015 to get a degree in physics. I live in Europe so I will have to get a bachelor's degree (3 years) then a master's degree (2 years). I am 26 years old and at the moment, I spend all of my free time re-learning...
  16. L

    What Are the Post-Graduation Plans for the BA/BS Class of 2015?

    Thought I'd start a thread for those of us who'll graduate next year - it seems like most of the people who'll graduate this year have already figured out what they want to do after graduation. I'm not sure how many of us there are, but are people thinking about graduate school or going into...
  17. G

    Will We Have Hoverboards by October 21 2015? The Science Behind the Fiction

    From a purely science FACT, not science FICTION, point of view, will we have Hoverboards by October 21 2015.
  18. T

    News Australia predicts China passes US by 2015

    Source: China boom sets our course CHINA GROWTH ENGINE OF THE WORLD China's output 1980: $US420bn ($A556 bn) 2005: $US8092bn. China is now the world's second-largest economy, twice the size of Japan. China as per cent of world output 1980: 3.2% 2005: 13.6% Last year China...
  19. Ivan Seeking

    Extrapolating current trends to the year 2015

    Based on all available data and using standard techniques. ...attachment coming...this is really scary.
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