Homework Statement
Dielectric medium inside capacitor consists of two types (check the pic). Capacitor's plates are connected to a source of constant tension U. Distance between the plates is d and their area is S. Find the electric charge of capacitor's plates.
Data given: U=500 V, d=2cm...
Homework Statement
If z=\frac{1}{x}[f(x-y)+g(x+y)], prove that \frac{\partial }{\partial x}(x^2\frac{\partial z}{\partial x})=x^2\frac{\partial^2 z}{\partial y^2}
Homework Equations
The Attempt at a Solution
I don't know how I'm supposed to find the partial derivative of z with respect to...
Homework Statement
Find \lim_{x \to 0}\frac{1-cosxcos2xcos3x}{1-cosx}
The Attempt at a Solution
Actually my book gives this continuation \lim_{x \to 0}\frac{1-cosx+cosx[1-cos2x+cos2x(1-cos3x)]}{1-cosx} but I don't know how author arrived there. Can anyone explain it to me?
Thank you
Homework Statement
Find the equation of plane which contains the line l:\left\{\begin{array}{l} x=t+2 \\y=2t-1\\z=3t+3 \end{array}\right., and makes the angle of \frac{2\pi}{3} with the plane \pi:x+3y-z+8=0.
The Attempt at a Solution
My attempt was to find the normal vector of plane which...
Hi tinytim,
I see now that the vectors are lineary dependent so 0 is the right answer.
I just want to have this question answered, are these operations I did legal?
Thank you
Hello Ray,
I did these operations: (-11\vec{m}\times\vec{n})\cdot(2\vec{m}+7\vec{n})=(-11\vec{m}\times\vec{n})\cdot2\vec{m}+(-11\vec{m}\times\vec{n})\cdot7\vec{n}=
=-22(\vec{m}\times\vec{n})\cdot\vec{m}-77(\vec{m}\times\vec{n})\cdot\vec{n}
So, according to definition, the vector...
Find (\vec{a}\times \vec{b})\cdot \vec{c} if \vec{a}=3\vec{m}+5\vec{n}, \vec{b}=\vec{m}-2\vec{n}, \vec{c}=2\vec{m}+7\vec{n}, |\vec{m}|=\frac{1}{2}, |\vec{n}|=3, \angle(\vec{m},\vec{n})=\frac{3\pi}{4}
This is my approach...
Homework Statement
Given \pi: \begin{cases}l_1: \frac{x-2}{4}\ = \frac{y-1}{2}\ = \frac{z+5}{-4} &\\l_2: \frac{x+4}{-2}\ = \frac{y+1}{0}\ = \frac{z}{1} & \end{cases} and the point M=(1,2,3) outside the plane. Find the projection of the line M_1P on plane \pi where P is the intersection point...
Hello!
I've solved my problem. I've been looking for this part of code:
srand(time(NULL));
random = arr[rand() % (sizeof(arr) / sizeof(arr[0]))];
Thank you.
Hello!
I've been trying to create an algorithm which picks a number randomly from array. P.S i have an array like A={1,4,-1,3,-7,2,-14} and I want to pick a number randomly from array.
Any idea?
Thank you.
Hello all!
Inside the water, body weights two times less than in air. Density of water is 1000kg/m^3. Find the density of body.
1. Well I tried this solution and I'm not sure if it's correct. I started from this principle Fa=W/2 (inside water force equals weight of the body divided by...
Borek, (it means "pie" in my language), thanks for the answer. I am just a type of autodidact, (i left school) so I'm just trying to get some things right. (Including tuning of my thinking).
Thank you again. :)
So it doesn't matter how atoms has O, oxidation number is always -2. This rule appears for all other elements right?
So for O4, O3, and O2, we have -2, what am I going to do for H2SO4, because H2 is +2 and O4 -2, so S is not going to have any oxidation number?
I would be very happy if you do...
Hi Borek,
I tried first this way:
\text{H}_2{SO}_4 + \text{CaCO}_3 \rightarrow \text{CaSO}_4 + \text{CO}_2 + \text{H}_2{O}
ON THE LEFT SIDE:
For \text{H}_2{SO}_4 (oxidation numbers are: H is +1, S is +6 and O4 -8)
For \text{CaCO}_3...
Hi there,
I have some trouble understanding redox reactions. Here is the question:
Sulphuric acid is one of the strongest inorganic acides which in some reaction shows oxidation properties. In which of reactions below, sulphuric acid acts as oxidating tool?
A.
\text{H}_2{SO}_4 +...
Thank you all.
http://www.math.nus.edu.sg/aslaksen/teaching/tides.html
Is this explanation correct? My book uses centrifugal force to explain the tides.
Thank you for your contribution.
Let me understand this. I have to create a plane which passes through that point. Another point is point of intersection. But to find that point i must have a direction vector of that plane and I don't have so can you help me with point of intersection. How can i find it?
So, when I have that...
Write equation of normal from point M(2,3,1) into line:l: \frac{x+1}{2}=\frac{y-0}{-1}=\frac{z-2}{3}.
I just have no idea about this problem. Any hint?
Thank you.
Hi all! I was just wondering if anyone can explain me why the tides (created by moon effect) are created on opposite sides.
(image is on attachment)
Thank you.
Hi QuantumBend! I don't understand you. You didn't give a good explanation. Can somebody help me to understand these two terms and give me some basic example?
Thank you.
Hi there! My physics teacher explained us a Ratherford model of atom and used some terms like "spin" and "quantic number". I'm havin trouble with these terms and maybe anybody can explain me the function of "quantic number" and spinnig and give me a basic example.
I just visited some web...
Hi!
for (int i=0; i<=9; i++)
{
for (int j=0; j<i; j++)
cout << " ";
for (int j=i; j<=9; j++)
cout << "*"
cout << endl;
}
Can anyone explain me what these lines are doing?
Thank you!
Hi guys!
I made a program in C, which count vowels on text, but it doesn't work.
Thats the code i have writed:
#include <stdio.h>
#include <string.h>
int main()
{
char buffer[80];
int counter;
printf("Enter a line of text: ");
fgets(buffer, sizeof(buffer), stdin)...