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**SuperLynx**- Replies: 1

Anyone here understand how a cross product works in relation to 3D ? I understand the core of what it does which is the third vector from the other two vectors but relating that to 3D space has been the issue. Here is my theory of how it works, suppose you have a sphere and a plane in a scene, the sphere is traveling on the Y axis, that is one vector, the plane is static, which is another vector, the X axis. When the sphere touches or hits the plane, the cross product would be the axis or vector to the right of the sphere and plane, suppose that is behind the sphere, when the sphere touches the plane, it will create a red mark which is the cross product of the sphere and the plane ?

Is my theory somewhat correct, or completely wrong ?

Maybe this will help; see how the B for Beta is between the two rows I want it only in the upper row ?

p\left ( R \right )= 1-2\mathbb\epsilon \left \begin{pmatrix}

e-e\\\

e-1

\end{pmatrix}\beta

thickhead wrote:

But I want to know why \mathbb is used?

I removed that part. How can I get the beta symbol near the top row ?

Yes, how did you do that, in the editor I linked too ?

I want to create a small beta symbol at the top near the e-e, currently the Beta symbol is between, as mentioned, the two rows when inserted.

p\left ( R \right )= 1-2\mathbb\epsilon \left \begin{pmatrix}

e-e\\\

e-1

\end{pmatrix}\beta

**SuperLynx**- Replies: 9

Hi, I'm using this editor and I want to create the B small in the top row, current it's between the rows ?

p\left ( R \right )= 1-2\mathbb\epsilon \left \begin{pmatrix}

e-e\\\

e-1\end{pmatrix}\mathbb\beta

thickhead wrote:

We represent a complex number in XY plane. real part is along or parallel to X axis and imaginary part is along or parallel to Y axis.e.g. Let us say you represent a land map as complex plane.say village B is x+jy distance from village A. x is distance along east ( displacement to west considered -ve)and y along north. You can cover the distance by 3 sessions of drive say. a+jb, c+jd, e+jf Then

at the same distance.

x+jy=a+jb+c+jd+e+jf

=(a+c+e)+j(b+d+f)

Real and imaginary parts must separately balance on both sides.

i.e. x=a+c+e and y=b+d+f If both are not satisfied you will not reach B.

If there is a village C such that AC=j(x+jy) ,C will be located such that

You're going to have to give a simpler example, until I can wrap my head around it ?

thickhead wrote:

34j is an imaginary number whose magnitude is 34. In an Argand diagram it is represented by a vertical line segment of magnitude 34. You can say j is a unit vector in y direction.

Why is it only in the Y direction, or it doesn't matter ?

thickhead wrote:

Hi Superlinx,

usually mathematicians use i and engineers use j . Both mean the same thing. 4+5i is represented by distance 4 along x axis and distance 5 parallel to y axis.You can say an "i" attached with a number rotates the vector by 90^0.

interestingly 4 i^2 means vector 4 along x axis is rotated by 180^0 and becomes -4 . this tallies with the concept that i^2=-1.

What if I write a formula 34j, what is that, literally, besides the number 34 ?

When do you use complex numbers ?

**SuperLynx**- Replies: 12

I'm trying to understand complex numbers for example 3j or 4i. I've been reading some sites on complex numbers but still can't wrap my ahead around it's purpose if I have the following formula;

45j + 4 = 49 and so what is the point of j ?

bobbym wrote:

Each base requires an equal number of symbols to represent any number. Base 2 has 2 numbers 0 and 1. Base 3 has 3 numbers, 0, 1, 2. Base 10 the one that we use requires 10 and base 16 requires 16.

I don't understand ?

Why must there be letters ?

bobbym - yes !

Thanks for the link Bob.

Why does with Base16 after 9 it goes into letters, then after F it goes back into numbers ?

How would I convert 145,89,200 into HEX values ?

bobbym wrote:

After 9 come the letters.

Base 10 is the system we use for arithmetic. Also, base 16 and hexadecimal (hex) are the same thing.

Sorry, I didn't understand what you meant ?

After 0, letters come into effect. What is Base10, does it include any letters ?

**SuperLynx**- Replies: 17

I'm trying to figure out Base16 and how to turn a RGB value such as; 145,34,203 into HEX values ?

From what I know after 9 it turns into letters, going to up F, with F=15, correct ? Why doesn't it go higher then F ?

Thanks same answer I got using my equation

**SuperLynx**- Replies: 4

I want to know how much percentage increase there is going from 320 to 502 ? At first I thought 502 / 320 = 1.5% that doesn't sound right !

**SuperLynx**- Replies: 4

Would you say the volume of an object are precise measurements of an object ?

CIV wrote:

You can not simply derive measurements such as height, width, and depth for a complicated shape such as a human body or car with more data. Even if you had this data, its extremely difficult to do. If your object was simple such as a cube, cylinder, or triangle and had more data,... we could calculate this a lot easier.

Not knowing any more than just the SA of say a box,... we can derive dimensions for say a box but there are infinitely many dimensions. This means the box can be of any shape or even size. If you give us the SA, L, and W, we can calculate the depth for example. If you only give the SA and L, that would mean the width and depth would be infinite.

I understand. A program I use only gave me those measurements from a irregular object, the program must be getting the information some how, some way, that is what I want to know ?

We both can agree that the program is not spitting out a random value for the surface area of the object !

bob bundy wrote:

Cover the solid in approximate cm squares and count them:

http://i.imgur.com/vC1eIA8.gif

Bob

I don't understand what you mean ?