|
More site info...
Calculus & Beyond | Forum profile
|
|
Forum profile page for Calculus & Beyond on http://www.physicsforums.com.
This report page is the aggregated overview from a single forum: Calculus & Beyond, located on the Message Board at http://www.physicsforums.com.
This forum profile page summarizes the general forum statistics such as: Users Activity, Forum Activity, and Top Authors, which are reported in either a table or graph below for a given reporting time period.
Additional forum profile information for "Calculus & Beyond" on the Message Board at http://www.physicsforums.com is also shown in the following ways:
1) Latest Active Threads
2) Hot Threads for Last Week
Warning: These statistics are generated using 'best efforts' and can experience delays and reporting errors at times. Please note that such statistics do not constitute a forum's popularity and/or exact posting volumes at any given reporting period.
|
|
|
|
|
Posting activity on Calculus & Beyond:
|
|
Week
|
Month
|
3 Months
|
|
Threads:
|
383
|
1,363
|
4,033
|
|
Post:
|
1,156
|
4,229
|
13,528
|
|
|
Calculus & Beyond Posting activity graph:
|
Top authors during last week:
user's latest post:
Equivalence Relations
Published (2009-11-25 10:49:00)
I can't come up with any justification of why this statement wouldn't be true, but I'm not having any success, either. I'll keep gnawing on it for a while.
user's latest post:
2nd order inhomogeneous ODE
Published (2009-11-25 08:59:00)
What you are talking about are linear differential equations but the equation you give is NOT linear. It is not just a matter of being "non-homogenous". For a non-homogeneous equation, the function on the right side (the one that is not multiplied by y or any of its derivatives) must be a function of the independent variable only. You certainly could make the substitution y= e T , but I don't see how you would then...
user's latest post:
rotation matrix proof
Published (2009-11-25 14:31:00)
Try this. Take the matrix [cos(x),sin(x),-sin(x),cos(x)] and diagonalize it. You'll get the same eigenvalues as A. Now figure out the relation between the basis where A looks like a rotation matrix and the basis of eigenvectors.
user's latest post:
The sum of a Fourier Series
Published (2009-11-25 14:28:00)
Originally Posted by HallsofIvy Since the Fourier series for g involves only sines, g is an odd function: that is it is extended exactly as it is with period . For x between and , . Surely you don't mean that. It is an appropriate translation of to the new interval.
user's latest post:
Triple Integrals. Need help...
Published (2009-11-25 10:31:00)
I think the theta angle is defined in a funny way in that excercise. If you have r going from zero to , then it goes from zero to zero.
user's latest post:
Equivalence Relations
Published (2009-11-25 11:21:00)
with no general way to shift the order of a & d in a combined multiplication, i'm thinking a counter example may be the way to go, with the two element interchange operations of permutation groups a good place to start...
user's latest post:
Identity for the probability of...
Published (2009-11-25 15:00:00)
Originally Posted by koab1mjr Given that n independent tosses having probability of p of coming up heads are made, show that an even number of heads results is 0.5(1+(q-p)^n) where q is 1-p, by proving the identity Sigma from i=0 to n/2 of (n choose 2i) (p^2i)(q^(n-2i))=0.5(((p+q)^n)+(q-p)^n) Originally Posted by koab1mjr … the problem is that the identity of (1/2)[(p+q)^n + (q-p)^n) doesnt show up at all?? Sorry, I'm not following...
user's latest post:
Partial Derivative: Chain Rule
Published (2009-11-25 12:40:00)
just for final confirmation... my calculation and my answer for this question is totally correct right?
user's latest post:
curl problem
Published (2009-11-25 07:51:00)
1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution I think for solving this problem I should write and and then do a lot of algerbra to work it out. Is it correct? Is there a better/another solution?
|
|
|
|
Latest active threads on Calculus & Beyond::
Started 4 days, 19 hours ago (2009-11-23 02:28:00)
by tiny-tim
(just got up …)
Originally Posted by koab1mjr
…for even, i got p^2q^(n-2), p^4q^(n-4) and so on …
( please use the X 2 tag just above the Reply box)
p 2 q n- 2 time what? p 4 q n-...
Started 2 days, 7 hours ago (2009-11-25 13:54:00)
by LCKurtz
Your limits are correct except the limit. Since you are limited to the first octant, neither nor can exceed . It's best to draw a picture to visualize it. Draw the first octant portion of the sphere and a radius from the origin to the boundary of the sphere somewhere in the middle. Label the two variables and . Think of moving the radius around the first octant and see ...
Started 3 days, 8 hours ago (2009-11-24 12:42:00)
by anirudh215
Originally Posted by rado5
2. Relevant equations
bac-cab
When and how is this ["bac - cab"] equation valid? The above equation is valid only as long as "a" is....?
Started 2 days, 10 hours ago (2009-11-25 10:46:00)
by Mark44
Originally Posted by Anonymous217
I can't stand having any math be unsolvable.
Better get used to it. Most integrals cannot be calculated exactly, so there are lots of techniques for numerical ...
Started 2 days, 14 hours ago (2009-11-25 06:35:00)
by arildno
1. Let the intersection be the origin in your coordinate system.
2. Now, let A's position at t (hours)=0 be 0.5 (km) on the right-hand side of the origin.
Then, A's position vector as a FUNCTION of time, A(t) will be:
(Agreed?)
Can you set up a similar vectorial position function for B?
3. Now that you have both position functions, how can you find the DISTANCE function...
Started 4 days ago (2009-11-23 20:46:00)
by lanedance
haven't checked your work, but notice you also have the original constraint, use that with the equation that you found
Started 2 days, 18 hours ago (2009-11-25 02:47:00)
by clamtrox
I haven't actually studied any statistics so there might be an easier way of doing this but this is how I'd do it...
Having a conditional probability means that you essentially have a 100% probability for the condition, that is
This gives you the probability density given the condition that x_1 < 2 x_2. You can then use that to find the probability that x_1 < x_2.
Started 2 days, 18 hours ago (2009-11-25 02:59:00)
by clamtrox
What is P(x_1 > y)? It's certainly not that. Maybe you should try integrating over f instead.
Started 2 days, 19 hours ago (2009-11-25 02:08:00)
by clamtrox
Yeah, your integration limits are incorrect. For P(x_1<x_2<x_3), start from x_1. Say it goes from zero to infinity. Then x_2 has to go from x_1 to infinity, and likewise x_3 goes from x_2 to infinity.
What's hard about solving the MGF?
I'm sure you know how to integrate an exponential function.
|
|
Hot threads for last week on Calculus & Beyond::
Started 2 days, 14 hours ago (2009-11-25 06:35:00)
by arildno
1. Let the intersection be the origin in your coordinate system.
2. Now, let A's position at t (hours)=0 be 0.5 (km) on the right-hand side of the origin.
Then, A's position vector as a FUNCTION of time, A(t) will be:
(Agreed?)
Can you set up a similar vectorial position function for B?
3. Now that you have both position functions, how can you find the DISTANCE function...
Started 1 week, 1 day ago (2009-11-19 16:25:00)
by Mark44
The roots of your characteristic equation are wrong. They should be r = -1 +/- i.
Started 5 days, 1 hour ago (2009-11-22 19:50:00)
by Mark44
Also, you have posted the same problem in another thread. Don't do this.
Started 1 week, 2 days ago (2009-11-18 20:27:00)
by Mark44
I would start with the right side, (x -y)(x + y) and use the distributive property to get
(x -y)(x + y) = (x - y)(x) + (x - y)(y).
Then use the commutative property of multiplication to rewrite (x - y)(y) as y(x - y), and the same for the other product. And so on...
Eventually you'll get to x^2 - y^2 and will have justified each step along the way by one of the basic properties of ...
Started 3 days, 12 hours ago (2009-11-24 08:38:00)
by Dick
If A is real and doesn't have real eigenvalues then it has two complex conjugate eigenvalues and their product is 1. That means they can be written in the form cos(x)+/-i*sin(x). Can you say why all these things are true? Isn't that starting to sound like a rotation matrix? Can you pick B to change the standard basis into a linear combination of those eigenvectors so that you get that form for ...
Started 5 days ago (2009-11-22 20:55:00)
by LCKurtz
You are extending f(x) periodically with period . You get the same thing when you integrate a periodic function over any period. That is, if g(x) has period P, then
That means you don't have to use to in your formulas for the coefficients; you can use 0 to , so you don't have to fiddle with changing the x 2 .
The other thing you are missing is using the Dirichlet ...
Started 2 weeks, 1 day ago (2009-11-12 13:59:00)
by Mark44
What you want is the perimeter of your circle, not the parameter.
In your integral for arc length, you are apparently going to calculate the arc length of the first quadrant of the circle, and then multiply by 4.
You have x^2 + y^2 = a^2. Either solve for y as a function of x, and then differentiate to get dy/dx, OR differentiate the given equation implicitly to get dy/dx. Put that ...
Started 4 days, 8 hours ago (2009-11-23 12:53:00)
by Math Jeans
Taylor expansions are an approximation of a function based on expansion around a point. They use polynomials to give a good analogue and are useful for very small variables. You would expect universal convergence from something like this, but this is not the case.
For this particular problem, you just need to know that you cannot divide by 0. Figure out at which values the derivative of your...
Started 3 days, 20 hours ago (2009-11-24 00:49:00)
by Mark44
I'm confused. In the other thread you started, you have
and in this one you have it as a 2nd-order ODE.
Since theta is a function of y and x', you really need partial derivatives, not ordinary derivatives. If theta were a function of a single variable, say x', then you could talk about d(theta)/dx' and d^2(theta)/dx'^2.
Having said that, how do you go from equation 1 to this ...
Started 1 week, 1 day ago (2009-11-19 16:49:00)
by flatmaster
I don't quite understand what you mean with your boundry conditions, do you mean...
when r=a, T=T1
when r=b, T=T2
Is this what you mean?
|
|
Size: 1,215 bytes
