l****z
发帖数: 29846 | 1 Often, we're hesitant to identify a problem out of fear we can't solve it.
Knowing that we have to live with something that we're unable to alter gives
us a good reason to avoid verbalizing it--highlighting it just makes it
worse.
While this sort of denial might be okay for individuals (emphasis on might),
it's a lousy approach for organizations of any size. That's because there
are almost certainly resources available that can solve a problem if you
decide it's truly worth solving.
Put yourself... 阅读全帖 |
|
g****t
发帖数: 31659 | 2 【 以下文字转载自 EE 讨论区 】
发信人: guvest (我爱你老婆Anna), 信区: EE
标 题: NYT: Solving a Riddle of Primes
发信站: BBS 未名空间站 (Mon May 20 22:48:57 2013, 美东)
分享下中国人的骄傲.
发信人: dionysus (悲剧的诞生), 信区: Mathematics
标 题: NYT: Solving a Riddle of Primes
发信站: BBS 未名空间站 (Mon May 20 21:27:36 2013, 美东)
http://www.nytimes.com/2013/05/21/science/solving-a-riddle-of-p
Solving a Riddle of Primes
By KENNETH CHANG
Published: May 20, 2013
Three and five are prime numbers — that is, they are divisible only by 1
and by themselves. So are ... 阅读全帖 |
|
x****d
发帖数: 2239 | 3 Copied from internet:
========================================================================
"We’re too broke to piss away money on some stupid wall that won’t solve
the illegal immigration problem. Here’s how to solve the illegal
immigration problem for free.
1. Establish a mandatory fine of $100,000 for each month that someone
employed an illegal immigrant.
2. Set up an 800-number for people to snitch on those employers.
3. Require each snitch to pay a $100 fee for each person they report, t... 阅读全帖 |
|
l******9
发帖数: 579 | 4 【 以下文字转载自 Statistics 讨论区 】
发信人: light009 (light009), 信区: Statistics
标 题: solve equations of integrals in python
发信站: BBS 未名空间站 (Fri Mar 21 12:21:31 2014, 美东)
I need to solve system equations of integrals in python 3.2.
from sympy import S, Eq, solve, integrals
import sympy as sym
import scipy.integrate as integ
x, b, c, m, v, L, u = S('x, b, c, m, v, L, u'.split())
equations = [Eq(m, integ.quad(xf(x, b, c), L, u))]
def xf(x, b,c):
return x*f(x,b,c)
def f(x, b, c):
return g(x, ... 阅读全帖 |
|
t******l
发帖数: 10908 | 5 回到前浪推荐的这本书本身。。。撇去该书里面艰深的内容，我摘抄一段该书的理念：
（声明一下不是说我要推荐读这本书，其实我也就是看看就完事了，并不死扣某一本
书。我只是说说不同的书的看法。）
P.258
8.2 Survival Geometry I
When you attempt Problems 8.1.1 - 8.1.3, you may wonder just what you may
assume and what you must prove. As you know, Euclidean geometry is based on
a very small set of undefined objects (including "points" and "lines") and
postulates or axioms (theorems that are assumed to be true, that lie "above"
proof) . In the interest of time, we will play fast and loose with this,
a... 阅读全帖 |
|
l******9
发帖数: 579 | 6 【 以下文字转载自 Statistics 讨论区 】
发信人: light009 (light009), 信区: Statistics
标 题: solve equations of integrals in python
发信站: BBS 未名空间站 (Fri Mar 21 12:21:31 2014, 美东)
I need to solve system equations of integrals in python 3.2.
from sympy import S, Eq, solve, integrals
import sympy as sym
import scipy.integrate as integ
x, b, c, m, v, L, u = S('x, b, c, m, v, L, u'.split())
equations = [Eq(m, integ.quad(xf(x, b, c), L, u))]
def xf(x, b,c):
return x*f(x,b,c)
def f(x, b, c):
return g(x, ... 阅读全帖 |
|
l******9
发帖数: 579 | 7 【 以下文字转载自 Statistics 讨论区 】
发信人: light009 (light009), 信区: Statistics
标 题: solve equations of integrals in python
发信站: BBS 未名空间站 (Fri Mar 21 12:21:31 2014, 美东)
I need to solve system equations of integrals in python 3.2.
from sympy import S, Eq, solve, integrals
import sympy as sym
import scipy.integrate as integ
x, b, c, m, v, L, u = S('x, b, c, m, v, L, u'.split())
equations = [Eq(m, integ.quad(xf(x, b, c), L, u))]
def xf(x, b,c):
return x*f(x,b,c)
def f(x, b, c):
return g(x, ... 阅读全帖 |
|
W*******n
发帖数: 4140 | 8 How to Solve the Idlib Problem by the Syrian Side?
Limin Wang
09/15/2018
How many troops from the Syrian and its allies can be used to finish any
apparent rebel pockets and to siege and retake Idlib? If the Idlib is being
made by foreign powers into a grave imminent threat to the Syrian side now,
then the Syrian side may use paratroops to take some crucial nodes of the
traffic networks in Idlib, and to take control of the traffic gates around
any major cities in Idlib. The Syrian side's army th... 阅读全帖 |
|
e*c
发帖数: 395 | 9 PLA要注意追赶了。
On Target With iPads
Close-Air Support Pilots Use Devices To Solve Map Problem
U.S. Marine Corps pilots in Afghanistan are using Apple iPads in life-and-
death situations downrange.
For about a year, pilots in Afghanistan have been using the devices to store
charts and maps necessary for conducting close-air support missions,
according to several pilots who have flown out of Camp Bastion in Helmand
province.
"It is giving me the ability to give better service to that infantryman on
th... 阅读全帖 |
|
g********d
发帖数: 4174 | 10 Online gamers help UW researchers solve AIDS mystery
Puget Sound Business Journal
Date: Monday, September 19, 2011, 4:53am PDT
University of Washington University of Washington Latest from The
Business Journals Pac-12 could become Pac-16Behind the Scenes with Patti
PayneUW No. 42, WSU No. 115 on college ranking list Follow this company
researchers have teamed up with gamers to make a breakthrough in AIDS
research that could unlock new drug treatments.
TechFlash reports the game at the center ... 阅读全帖 |
|
m******t
发帖数: 273 | 11 【 以下文字转载自 Statistics 讨论区 】
发信人: myregmit (myregmit), 信区: Statistics
标 题: solve an optimization model with integral as constraints
发信站: BBS 未名空间站 (Wed Mar 19 22:21:44 2014, 美东)
I need to solve a mathematical optimization model with integral as
constraints.
Min. | s1 - k1 | + | s2- k2 |
s.t.
integral_from_0_to_M of f(x) = 1
s1 = integral_from_0_to_M of x * f(x)
s2 = integral_from_0_to_M of x^2 * f(x)
M, k1 and k2 are positive numbers
f(x) is a proba... 阅读全帖 |
|
m******t
发帖数: 273 | 12 【 以下文字转载自 Quant 讨论区 】
发信人: myregmit (myregmit), 信区: Quant
标 题: solve integral eq. embeeded with another integral eq.
发信站: BBS 未名空间站 (Sun Mar 23 14:20:18 2014, 美东)
I need to solve an integral equation embedded with another integral equation
by python 3.2 in win7.
There are 2 integral equations.
The code is here:
import numpy as np
from scipy.optimize.minpack import fsolve
from numpy import exp
from scipy.integrate.quadpack import quad
import matplotlib.pyplot as plt
impor... 阅读全帖 |
|
|
s**t
发帖数: 4 | 14 推荐一本书 - solve your children's sleep problem
Solve Your Child's Sleep Problems: New, Revised, and Expanded Edition
是医生推荐的，也是有朋友推荐的。
照着书上说的进行了TRAINIG,现在总算可以睡好了。当然夜里11点和5点还要喂俩次，
关键是入睡没有那么痛苦了 |
|
|
v********0
发帖数: 2 | 16 【 以下文字转载自 CS 讨论区 】
发信人: virtual150 (Cool Mountain), 信区: CS
标 题: Solving long polling scalability problem.
发信站: BBS 未名空间站 (Mon Aug 9 01:28:05 2010, 美东)
Long polling keeps a connection to the server for every request thus
intrinsically having scalability problem.
Anyone on the board has alternatives or a way to solve the issue?
Btw, for those who don't know what I am talking about, please take a look at
the following wiki page:
http://en.wikipedia.org/wiki/Comet_(programming) |
|
w*****g
发帖数: 1415 | 17 【 以下文字转载自 JobHunting 讨论区 】
发信人: wuchang (wuchang), 信区: JobHunting
标 题: Need idea with "Tell us a time you solve a technical problem"
发信站: BBS 未名空间站 (Thu Sep 7 10:23:51 2017, 美东)
I just cannot find an interesting story for "Tell us a time you solve a
technical problem". Can someone help provide some ideas? Many thanks! |
|
a****d
发帖数: 1919 | 18 http://www.theonion.com/articles/sonofabitch-mouse-solves-maze-researchers-spent-mo,2432/
News
Son-Of-A-Bitch Mouse Solves Maze Researchers Spent Months Building
IOWA CITY, IA—University of Iowa neuroscientists studying spatial learning
and the effects of stress on memory announced Tuesday that a little son-of-a
-bitch mouse ruined an experiment on cognitive performance by effortlessly
navigating a maze that researchers spent nearly a year designing and
constructing.
The test subject, a common h |
|
f****e
发帖数: 15 | 19
: ~~~~~~~~~
no ba, he meant to solve algebraic equation.
i don't think matlab can solve every arbitrary algebraic equation. |
|
m****d
发帖数: 331 | 20 When i call Cplex in GGAMS to solve a MIP problem, it seems that Cplex gives
me weired results. It first fixes the binary variables to minimize the
objective function, then solve the rest problem as a LP problem.
This gives me infeasible solutions. for example, a constraint like:
q(i,g,t)<=M*u(i,g,t), where q are contious variables and u are bianry
variables, M is just a parameter.
In the .list file, i found that Cplex just gives 0 to all u(i,g,t). But, q(i,g
,t) has to be positive so that it ca |
|
o*******e
发帖数: 186 | 21 【 以下文字转载自 Computation 讨论区 】
发信人: otherwise (慕悠), 信区: Computation
标 题: Need help on solving PDE in Matlab
发信站: BBS 未名空间站 (Mon Aug 21 22:30:02 2006)
I don't know how to solve the following PDEs in Matlab:
d f1/dx = f1+f2*exp(-t)
d f2/dt = f1*exp(-x)+ f2;
where f1, f2 are functions of (x,t),
I.C. f1 = 1 at x = 0;
B.C. f2 = 0 at t = 0;
I do appreciate very much if you have any idea about it. Thank you! |
|
o*******e
发帖数: 186 | 22 【 以下文字转载自 Computation 讨论区 】
发信人: otherwise (慕悠), 信区: Computation
标 题: Need help on solving PDE in Matlab
发信站: BBS 未名空间站 (Mon Aug 21 22:30:02 2006)
I don't know how to solve the following PDEs in Matlab:
d f1/dx = f1+f2*exp(-t)
d f2/dt = f1*exp(-x)+ f2;
where f1, f2 are functions of (x,t),
I.C. f1 = 1 at x = 0;
B.C. f2 = 0 at t = 0;
I do appreciate very much if you have any idea about it. Thank you! |
|
d******s
发帖数: 180 | 23 http://www.nytimes.com/2013/05/21/science/solving-a-riddle-of-p
Solving a Riddle of Primes
By KENNETH CHANG
Published: May 20, 2013
Three and five are prime numbers — that is, they are divisible only by 1
and by themselves. So are 5 and 7. And 11 and 13. And for each of these
pairs of prime numbers, the difference is 2.
Mathematicians have long believed that there are an infinite number of such
pairs, called twin primes, meaning that there will always be a larger pair
than the largest one found.... 阅读全帖 |
|
m******t
发帖数: 273 | 24 【 以下文字转载自 Statistics 讨论区 】
发信人: myregmit (myregmit), 信区: Statistics
标 题: solve an optimization model with integral as constraints
发信站: BBS 未名空间站 (Wed Mar 19 22:21:44 2014, 美东)
I need to solve a mathematical optimization model with integral as
constraints.
Min. | s1 - k1 | + | s2- k2 |
s.t.
integral_from_0_to_M of f(x) = 1
s1 = integral_from_0_to_M of x * f(x)
s2 = integral_from_0_to_M of x^2 * f(x)
M, k1 and k2 are positive numbers
f(x) is a proba... 阅读全帖 |
|
m******t
发帖数: 273 | 25 【 以下文字转载自 Quant 讨论区 】
发信人: myregmit (myregmit), 信区: Quant
标 题: solve integral eq. embeeded with another integral eq.
发信站: BBS 未名空间站 (Sun Mar 23 14:20:18 2014, 美东)
I need to solve an integral equation embedded with another integral equation
by python 3.2 in win7.
There are 2 integral equations.
The code is here:
import numpy as np
from scipy.optimize.minpack import fsolve
from numpy import exp
from scipy.integrate.quadpack import quad
import matplotlib.pyplot as plt
impor... 阅读全帖 |
|
n*********3
发帖数: 534 | 26 I see A lot of books places say that Euler solved the Basel problem. But
they only show the results, and not how.
Can anyone show how?
Lookacar and others?
"Notably, Euler directly proved the power series expansions for e and the
inverse tangent function. (Indirect proof via the inverse power series
technique was given by Newton and Leibniz between 1670 and 1680.) His daring
use of power series enabled him to solve the famous Basel problem in 1735 (
he provided a more elaborate argument in 1741)... 阅读全帖 |
|
i***0
发帖数: 8469 | 27 Solve this task using recursion. how to ?
“Given a string build all possible non-zero length substrings from it.
Example
Input:
abc
Output:
a
b
c
ab
ac
bc
abc
Solve this task using recursion.” |
|
m******t
发帖数: 273 | 28 【 以下文字转载自 Statistics 讨论区 】
发信人: myregmit (myregmit), 信区: Statistics
标 题: solve an optimization model with integral as constraints
发信站: BBS 未名空间站 (Wed Mar 19 22:21:44 2014, 美东)
I need to solve a mathematical optimization model with integral as
constraints.
Min. | s1 - k1 | + | s2- k2 |
s.t.
integral_from_0_to_M of f(x) = 1
s1 = integral_from_0_to_M of x * f(x)
s2 = integral_from_0_to_M of x^2 * f(x)
M, k1 and k2 are positive numbers
f(x) is a proba... 阅读全帖 |
|
s*w
发帖数: 329 | 29 Once I used a program called "delphi" to solve that. It can
solve
both linear and nonlinear PB equation. The speed is pretty
good.
Ask your boss to buy it. :) |
|
p**n
发帖数: 10 | 30 I would like to solve the following diffusion equation in 3 dimension
using finite element method.
-grad{D(x,y,z)grad[U(x,y,z)]}+h(x,y,z)U(x,y,z)=0
subject to mixed boundary conditions
This is a pretty standard problem. I was wondering if any one knows
there are any 3D FEM matlab code (or other codes) that can solve this
equation (and I can download)? If you know please let me know
bow!!! |
|
l******9
发帖数: 579 | 31 I need to solve system equations of integrals in python 3.2.
from sympy import S, Eq, solve, integrals
import sympy as sym
import scipy.integrate as integ
x, b, c, m, v, L, u = S('x, b, c, m, v, L, u'.split())
equations = [Eq(m, integ.quad(xf(x, b, c), L, u))]
def xf(x, b,c):
return x*f(x,b,c)
def f(x, b, c):
return g(x, b,c) * (x/b)**(c-1) * sym.exp(-x/b)
def g(x, b, c):
c = 1+c // TypeError: unsupported operand type(s) for +: 'int' and '
tuple'
L = 1
u = 10
... 阅读全帖 |
|
m******t
发帖数: 273 | 32 【 以下文字转载自 Quant 讨论区 】
发信人: myregmit (myregmit), 信区: Quant
标 题: solve integral eq. embeeded with another integral eq.
发信站: BBS 未名空间站 (Sun Mar 23 14:20:18 2014, 美东)
I need to solve an integral equation embedded with another integral equation
by python 3.2 in win7.
There are 2 integral equations.
The code is here:
import numpy as np
from scipy.optimize.minpack import fsolve
from numpy import exp
from scipy.integrate.quadpack import quad
import matplotlib.pyplot as plt
impor... 阅读全帖 |
|
W*****2
发帖数: 1043 | 33 America's education is the best in the world:-)
I have to say that I cannot solve these math problems:-) |
|
W*****2
发帖数: 1043 | 34 LOL
I am broke because I cannot solve the math problems:-) |
|
W*****2
发帖数: 1043 | 35 Obama is a genius, he will solve these math problems.
Good luck, Obama!!! |
|
|
A*****e
发帖数: 64 | 37 I am proctoring an exam now. When making the exam, I was trying to simplify
the calculations rather focusing on the conceptual understanding. So, one
of the questions has such a step - solve (x+4)(x-5) = 0. I just saw a
student spent a quite long time to do this :
(x+4)(x-5) = x^2-5x+4x -20 = x^2-x-20 = 0, then x = (1+/-sqrt(1-4*(-20)))/2
= -4 and 5.
This is actually not bad. Very frequently I see some silly mistakes like
exp(-t) + exp(-4t) = exp(-5t). Should I laugh or feel sad? When I firs... 阅读全帖 |
|
m********s
发帖数: 414 | 38 【Solved】最近银行间ACH问题比较大，billpay速度明显放慢， 付款速度的确放慢了
，GHOST518 无责，被我冤枉了， 再次道歉一下
原文：
急寻GHOST518， 根据你所说，给我的billpay 12/3到帐，今。。。。 |
|
j***t
发帖数: 50 | 39 How to solve this problem? what algorithm should be used?
For a list of strings, find the largest subsets, within it, no string is a
prefix of another one.
For example,
a, abc, acd, df, dfe
The largets sub sets would be (both are of size 3):
abc, acd, def
or
abc acd, dfe
|
|
g*******m
发帖数: 182 | 40 马上有一个onsite interview, 是个小公司，vice president告诉我面试的时候要有一
个“ skill exercise”，不知道怎么回
事，发信过去问了一下，对方解释说是“problem solving test"，还是不明白！
从来没有碰到过，望大虾解释一下这个是什么测试，该如何准备，已经很多年没有考过
试，不想太丢人。
谢谢。 |
|
l*****a
发帖数: 14598 | 41 不好意思，看错题目了。
不是verification..
是solve... |
|
l********8
发帖数: 668 | 42 一家公司要电面programming/puzzle solving。 并说 You can choose any of the
regular programming languages (preferably one mentioned in the job
description). The focus will also be directed more towards general coding
skills and data structures.
在job description中的programming languages，我就用过C/C++. 但自从工作以来，
都是用SAS， R。 再未用过C/C++。 这怎么办？ |
|
w*****g
发帖数: 1415 | 43 I just cannot find an interesting story for "Tell us a time you solve a
technical problem". Can someone help provide some ideas? Many thanks! |
|
z*********n
发帖数: 1451 | 44 1. Find a PXJ problem, the harder the better
2. Solve it
3. Write down how you did 2. |
|
a*****g
发帖数: 19398 | 45 Elementary students solve math problems for a good cause
摘要：
学校实施了这样一个 program ——
小学生完成数学家庭作业，
然后自己再找人（父母、朋友等）为此向慈善机构捐款。
By Kevin Graham
For Heritage Media
http://www.heritage.com/articles/2013/12/19/dexter_leader/news/
DEXTER — For a group of students at Wylie Elementary in Dexter, math is
adding up to more than figures. The solution to this problem equals dollars
and cents for a good cause.
Students at the school, which serves just over 600 third and fourth graders,
raised over $7,000 for St. ... 阅读全帖 |
|
s***n
发帖数: 1280 | 46 我觉得这本书适合那些备考AIME及USA(J)MO的孩子或是对从事数学相关专业感兴趣的孩
子，不太适合那些针对SAT或是AMC 10/12的孩子。
AOPS的系统教科书厚是因为它要从零讲起，不仅要讲解很多基础知识点，还要涵盖竞赛
知识点和解题技巧。另外，AOPS的竞赛备考书主要涵盖竞赛知识点和解题技巧，基础知
识点最多只总结下，并不厚。
Zeitz的ACOPS并不是传统意义上的数学教科书，或是竞赛备考书。它主要不是传授具体
的解题技巧，而是训练抽象的解题思维和能力 - 当你碰到一个以前没见过的题型时，
如何去找到解法。这些方面的训练对解决AIME难题或USA(J)MO题有帮助。
要真正理解和掌握ACOPS里的解题思维，需要有一定的解题能力和底子。很多备考AMC的
孩子还不到这个水平。我觉得还是AOPS的书更适合他们。
ACOPS自介：
"This is a book about mathematical problem solving for college-level novices
. By this
I mean bright people who know some mathe... 阅读全帖 |
|
s*****w
发帖数: 1527 | 47 address is there, but complaining about no shipping method etc.
how do you solve it ?
many thanks ! |
|
U*********r
发帖数: 68 | 48 Stock market is soaring. So the fiscal cliff problem is solved? Sounds like
too easy to be true. |
|
q*x
发帖数: 683 | 49 of course it will be solved. Looking back the history, a country of that
size won't make a dent for too long. |
|
c*******9
发帖数: 6411 | 50 do not think yahoo solves the tax issue of alibaba, the investment holding
company still need to pay tax if sell the alibaba stake. it is just that for
yahoo, it do not have to deal with it anymore |
|
