# 1.15 Game 2302-0145: getting started with the vector dot product  (Page 2/20)

 Page 2 / 20

## Listings

• Listing 1 . Source code for the method named GM02.ColMatrix3D.dot.
• Listing 2 . Source code for the method named GM02.Vector3D.dot.
• Listing 3 . Source code for the method named GM02.Vector3D.angle.
• Listing 4 . The actionPerformed method in the program named DotProd2D01.
• Listing 5 . Format the dot product value for display in the GUI.
• Listing 6 . Beginning of the actionPerformed method in the program named DotProd2D02.
• Listing 7 . Compute the dot product and the angle between the two vectors.
• Listing 8 . Source code for the game-math library named GM02.
• Listing 9 . Source code for the program named DotProd2D01.
• Listing 10 . Source code for the program named DotProd2D02.
• Listing 11 . Source code for the program named DotProd3D01.
• Listing 12 . Source code for the program named DotProd3D02.

## Preview

The homework assignment for this module was to study the Kjell tutorial through Chapter 10, Angle between 3D Vectors .

I won't repeat everything that Dr. Kjell has to say. However, there are a few points that I will summarize in this section.

Basic definition of the vector dot product

The vector dot product is a special way to multiply two vectors to produce a real result. A description of the vector dot product follows.

The vector dot product:

The vector dot product of two vectors is the product of the lengths of the vectors multiplied by the cosine of the angle between them

By the angle between them , I mean the angle that would be formed if you were to draw the two vectors with theirtails in the same location.

For example, Figure 3 shows a black vector and a magenta vector drawn with their tails at the origin. Eyeballing the picture suggests that the anglebetween the two vectors is forty or fifty degrees.

Figure 3 Two vectors with their tails at the origin, program DotProd2D02.

Can do more than eyeball

Fortunately, we can do more than eyeball the angle between two vectors. Figure 3 shows the screen output produced by the program named DotProd2D02 that I will explain in this module. DotProd2D02 is a 2D program. I will also explain a 3D version named DotProd3D02 in this module as well.

In Figure 3 , the top four user input fields allow the user to enter the x and y coordinate values of two vectors according to the labels that identify thosefields. When the user clicks the OK button, the first vector is drawn in black with its tail at the origin and the second vector is drawn in magenta withits tail at the origin. The dot product of the two vectors is computed and displayed in the bottom left text field, and the angle between the two vectorsis computed and displayed in the bottom right text field.

Don't need to know the angle between the vectors

Upon seeing the description of the dot product given above , you may reasonably be concerned about needing to know the angle between the vectors before you can compute thedot product. Fortunately, as you will see later , it is possible to compute the dot product of two vectors without knowing the angle. In fact, being able to compute the dot product is oneway to determine the angle between two vectors.

#### Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
how did you get the value of 2000N.What calculations are needed to arrive at it
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!