Please post any and all homework or other textbookstyle problems in one of the Homework & Coursework Questions...

Feb2313 09:24 AM
micromass

1 
40,149 
Hi All,
I am reading a paper in which the following integral is presented
$$\int_{\infty}^{ctx}...

Sep1713 11:01 AM
muzialis

7 
944 
I wanted to do this integral $$\int_a^b \frac{dx}{1x^2} $$ and I was able to get the right answer with the...

Sep1713 10:51 AM
jackmell

15 
975 
My textbook states that "For the integral test to apply, it is not necessary that f be always decreasing. What is...

Sep1613 10:06 AM
pasmith

1 
673 
Assume that a function f:\to\mathbb{R} is differentiable in all points of its domain, and that the derivative...

Sep1513 06:43 AM
jostpuur

2 
648 
I'm trying to find a way to use calculus without infinitesimals and I'm stuck on this physics problem.
It's a...

Sep1413 10:38 AM
gopher_p

2 
693 
The mass of a sphere with density as a function of radius is
M=4\pi \int_0^r\rho(r) r^2dr
Lets say the...

Sep1413 03:01 AM
JJacquelin

10 
857 
Everything I've encountered in physics so far allows infinitesimal numbers to be manipulated as real numbers. But...

Sep1413 01:16 AM
Jd0g33

3 
718 
Is \frac{∂y}{∂x}×\frac{∂x}{∂z}=\frac{∂y}{∂z}?

Sep1313 10:01 PM
arildno

7 
698 
Suppose we are taking the variation of a multiple integral and the integrand contains some terms with \frac{\partial...

Sep1313 12:57 PM
pasmith

7 
851 
Ok, there are a couple of other threads about this, but they don't seem to answer my question.
If I take the double...

Sep1313 11:34 AM
D H

13 
862 
When the limit of a function turns out to be infinity ,how should we interpret it ?
For ex. we have \lim_{x \to...

Sep1213 05:46 PM
Stephen Tashi

11 
765 
Hey there!
I'm trying to calculate the Fourier Series for sin2x on
For a0 I found 1/2. (By determining the...

Sep1213 04:31 AM
vanhees71

4 
1,045 
Hello everyone, my first post :shy:
I'm reading Zee's 'QFT in a Nutshell' and I came to one thing that bothers me ...

Sep1113 08:40 AM
D H

9 
630 
My professor, when doing trig substitution in lecture, always defines theta between certain intervals and when he...

Sep1113 04:07 AM
CAF123

4 
523 
Hi,
i am trying to develop a CDF from a given MGF. The standard way of using the inverse Laplace transform etc.. is...

Sep1013 03:44 PM
mathman

1 
572 
Hello,
I have a doubt on how to differentiate a complex function f:ℂ→ℂ defined as follows: f(z)=zz^* where the *...

Sep1013 12:25 PM
mathwonk

12 
910 
Hi! I do not understand the math used in the beginning of this video: http://www.youtube.com/watch?v=wulBI4ToZQ4
...

Sep1013 11:26 AM
Nikitin

2 
581 
I have a diffraction grating through which I shined a 532 nm laser. A detector which can pan 360˚ was rotated around...

Sep1013 10:44 AM
Johnny Davens

0 
382 
I posted a question on stack about generalizing the methods of volumes by slicing & volumes of revolutions & came...

Sep913 05:09 PM
bolbteppa

2 
536 
I really want to learn calculus I and II by the end of this month, anyone willing to join me? Another person would...

Sep913 04:35 PM
new_at_math

0 
539 
Hey. I'm looking for a proof of:
Theorem: If f \in C^1(\mathbb{T}), then the Fourier series converges to f uniformly...

Sep813 03:33 PM
brmath

6 
899 
So I've been spending a lot of time lately trying to figure out why an integral will give you the area under the...

Sep813 12:09 PM
arildno

4 
577 
Use the chain rule to show that
dz/dx = (cos(theta) * dz/dr)  (1/r * sin(theta) dz/dtheta) and
dz/dy =...

Sep813 03:59 AM
CompuChip

1 
479 
so this is from math lab
x is a 2 kHz sinewave
>> n = 0:1023;
>> t = n/8000;
>> x = sin(2000*2*pi*t);
>> X =...

Sep713 08:28 AM
ZetaGuy

17 
2,087 
I want to substitute ds by dt in the FrenetSerret Formulas where κ is the curvature and is the torsion:...

Sep713 03:23 AM
vanhees71

1 
476 
This is from a functional equation , i think there is no points in posting it here this is what i ant to prove the...

Sep613 04:01 PM
Andrax

2 
432 
Hi, I was reading something on conservative fields, in this example \phi is a scalar potential. (Please refer to the...

Sep613 03:03 PM
verty

4 
447 
how is the logistic function characterized by the differential equation
df(x)/dx = f(x)(1f(x))
x), but this is...

Sep613 07:55 AM
pasmith

1 
547 
Hello,
I am wondering if there is a forumula for the number of possible positions in chess after n moves. I...

Sep513 08:07 PM
AlephZero

7 
600 
Hi all,
I am trying to hard to understand integral's transform.
While an interpretation of Fourier transform is...

Sep513 10:38 AM
bolbteppa

3 
1,062 
i am having an issue finding the variational average of a stiffness matrix.
The stiffness matrix is of a...

Sep413 09:15 PM
tricha122

0 
548 
Hi,
I want to calculate a volume integral of a function f(r,theta). The limits for azimuthal and polar angle is of...

Sep413 02:35 AM
Astrum

7 
551 
Hi there,
I have what I suspect is a straightforward question.
I wish to take the total derivative of the...

Sep313 03:38 PM
mathman

1 
462 
how do we take derivative of modulus of a function??

Sep213 08:38 PM
brmath

2 
631 
I do not understand the following integral:
\int^{\infty}_{0}2e^{2+jωt}dt = \frac{j2e^{2}}{\omega}
Why is it not...

Sep213 03:47 PM
jackmell

4 
603 
Hi! Does anybody know if there is something in common between Bernstein functions and Bernstein polynomials except the...

Sep213 04:41 AM
Tatianaoo

2 
401 
So dx means an infinitesimally small change in x. Why is the slope written \frac{dy}{dx} instead of \frac{f(x)}{dx}...

Sep113 08:51 PM
Mandelbroth

7 
755 
Hi PFmembers.
My intuition tells me that: Given a divergence free vector field \mathbf{F} , then the curl of the...

Aug3113 04:32 AM
Wuberdall

2 
646 
I am interested to know whether the modified Bessel functions of the second kind, also known as BesselK, defined as
...

Aug2913 08:38 AM
kd6ac

0 
568 
i am using textbook in classical mechanics by douglas gregory. It is known that rate of change of displacement with...

Aug2913 08:16 AM
HallsofIvy

4 
611 