# 2.2 Vectors in three dimensions  (Page 3/14)

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Find the distance between points ${P}_{1}=\left(1,-5,4\right)$ and ${P}_{2}=\left(4,-1,-1\right).$

$5\sqrt{2}$

Before moving on to the next section, let’s get a feel for how ${ℝ}^{3}$ differs from ${ℝ}^{2}.$ For example, in ${ℝ}^{2},$ lines that are not parallel must always intersect. This is not the case in ${ℝ}^{3}.$ For example, consider the line shown in [link] . These two lines are not parallel, nor do they intersect.

You can also have circles that are interconnected but have no points in common, as in [link] .

We have a lot more flexibility working in three dimensions than we do if we stuck with only two dimensions.

## Writing equations in ℝ 3

Now that we can represent points in space and find the distance between them, we can learn how to write equations of geometric objects such as lines, planes, and curved surfaces in ${ℝ}^{3}.$ First, we start with a simple equation. Compare the graphs of the equation $x=0$ in $ℝ,{ℝ}^{2},\phantom{\rule{0.2em}{0ex}}\text{and}\phantom{\rule{0.2em}{0ex}}{ℝ}^{3}$ ( [link] ). From these graphs, we can see the same equation can describe a point, a line, or a plane.

In space, the equation $x=0$ describes all points $\left(0,y,z\right).$ This equation defines the yz -plane. Similarly, the xy -plane contains all points of the form $\left(x,y,0\right).$ The equation $z=0$ defines the xy -plane and the equation $y=0$ describes the xz -plane ( [link] ).

Understanding the equations of the coordinate planes allows us to write an equation for any plane that is parallel to one of the coordinate planes. When a plane is parallel to the xy -plane, for example, the z -coordinate of each point in the plane has the same constant value. Only the x - and y -coordinates of points in that plane vary from point to point.

## Rule: equations of planes parallel to coordinate planes

1. The plane in space that is parallel to the xy -plane and contains point $\left(a,b,c\right)$ can be represented by the equation $z=c.$
2. The plane in space that is parallel to the xz -plane and contains point $\left(a,b,c\right)$ can be represented by the equation $y=b.$
3. The plane in space that is parallel to the yz -plane and contains point $\left(a,b,c\right)$ can be represented by the equation $x=a.$

## Writing equations of planes parallel to coordinate planes

1. Write an equation of the plane passing through point $\left(3,11,7\right)$ that is parallel to the yz -plane.
2. Find an equation of the plane passing through points $\left(6,-2,9\right),$ $\left(0,-2,4\right),$ and $\left(1,-2,-3\right).$
1. When a plane is parallel to the yz -plane, only the y - and z -coordinates may vary. The x -coordinate has the same constant value for all points in this plane, so this plane can be represented by the equation $x=3.$
2. Each of the points $\left(6,-2,9\right),$ $\left(0,-2,4\right),$ and $\left(1,-2,-3\right)$ has the same y -coordinate. This plane can be represented by the equation $y=-2.$

Write an equation of the plane passing through point $\left(1,-6,-4\right)$ that is parallel to the xy -plane.

$z=-4$

As we have seen, in ${ℝ}^{2}$ the equation $x=5$ describes the vertical line passing through point $\left(5,0\right).$ This line is parallel to the y -axis. In a natural extension, the equation $x=5$ in ${ℝ}^{3}$ describes the plane passing through point $\left(5,0,0\right),$ which is parallel to the yz -plane. Another natural extension of a familiar equation is found in the equation of a sphere.

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
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
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