If Z, Y, and A are the midpoints of triangle VWX, what is true about AY and XV

I can't figure out how to do (i + j) x (i x j)for vector calc

Vinil7 [7]

In three dimensions, the cross product of two vectors is defined as shown below

$\begin{gathered} \vec{A}=a_1\hat{i}+a_2\hat{j}+a_3\hat{k} \\ \vec{B}=b_1\hat{i}+b_2\hat{j}+b_3\hat{k} \\ \Rightarrow\vec{A}\times\vec{B}=\det (\begin{bmatrix}{\hat{i}} & {\hat{j}} & {\hat{k}} \\ {a_1} & {a_2} & {a_3} \\ {b_1} & {b_2} & {b_3}\end{bmatrix}) \end{gathered}$

Then, solving the determinant

$\Rightarrow\vec{A}\times\vec{B}=(a_2b_3-b_2a_3)\hat{i}+(b_1a_3+a_1b_3)\hat{j}+(a_1b_2-b_1a_2)\hat{k}$

In our case,

$\begin{gathered} (\hat{i}+\hat{j})=1\hat{i}+1\hat{j}+0\hat{k} \\ \text{and} \\ (\hat{i}\times\hat{j})=(1,0,0)\times(0,1,0)=(0)\hat{i}+(0)\hat{j}+(1-0)\hat{k}=\hat{k} \\ \Rightarrow(\hat{i}\times\hat{j})=\hat{k} \end{gathered}$

Where we used the formula for AxB to calculate ixj.

Finally,

$\begin{gathered} (\hat{i}+\hat{j})\times(\hat{i}\times\hat{j})=(1,1,0)\times(0,0,1) \\ =(1\cdot1-0\cdot0)\hat{i}+(0\cdot0-1\cdot1)\hat{j}+(1\cdot0-0\cdot1)\hat{k} \\ \Rightarrow(\hat{i}+\hat{j})\times(\hat{i}\times\hat{j})=1\hat{i}-1\hat{j} \\ \Rightarrow(\hat{i}+\hat{j})\times(\hat{i}\times\hat{j})=\hat{i}-\hat{j} \end{gathered}$

Thus, (i+j)x(ixj)=i-j

8 0

10 months ago

The radius of the base of the cylinder is 2x cm and the height of the cylinder is h cm.

valentina_108 [34]

Answer:

h = 9x

Step-by-step explanation:

Given: i. for the cylinder, base radius = 2x cm, height = h cm

ii. for the sphere, radius = 3x cm

iii. volume of the cylinder = volume of the sphere

volume of a cylinder is given as;

volume = $\frac{1}{3}$ $\pi$ $r^{2}$ h

where: r is its base radius and h the height

volume of the given cylinder = $\frac{1}{3}$ $\pi$ x $(2x)^{2}$ x h

= $\frac{1}{3}$ $\pi$ x 4 $x^{2}$ x h

= $\frac{4}{3}$ $\pi$ $x^{2}$ h

volume of a sphere = $\frac{4}{3}$ $\pi$ $r^{3}$

where r is the radius.

volume of the given sphere = $\frac{4}{3}$ $\pi$ x $(3x)^{3}$

= $\frac{4}{3}$ $\pi$ x 9 $x^{3}$

= 12 $\pi$ $x^{3}$

Since,

volume of the cylinder = volume of the sphere

Then we have;

$\frac{4}{3}$ $\pi$ $x^{2}$ h = 12 $\pi$ $x^{3}$

4 $\pi$ $x^{2}$ h = 36 $\pi$ $x^{3}$

subtract $x^{2}$ from both sides

4 $\pi$ h = 36 $\pi$ x

divide both sides by 4 $\pi$

h = $\frac{36\pi x}{4\pi }$

= 9x

h = 9x

5 0

2 years ago

The speed of the international space station is 27,576 kilometres per hour.

Dmitriy789 [7]

(27576km/hr)(24hr/day)(orbits/42600km)=orbits/day=15.53

So the station makes 15 FULL orbits per day

(27576km/h)(1000m/km)(h/3600s)=7660m/s

7 0

2 years ago

I don't really get it. it would be amazing if you help and show work

eimsori [14]

Change of y / over change of x
Go over 4, up 45
B is your correct answer
Hope this helps!

7 0

3 years ago

Read 2 more answers

Write a differential equation that models the given situation. The stated rate of change is with respect to time t. (Use k for t

Alex787 [66]

The differential equation that models the given situation will be dy/dt = K(N - y).

<h3>How to compute the equation?</h3>

Let y = number of individuals who have heard about the product.

Let N - y = this who haven't heard about the product.

From the given statement, the rate for change will be t = dy/dt. Therefore, the differential equation that models the given situation will be dy/dt = K(N - y).

Learn more about equations on:

brainly.com/question/2972832

#SPJ1

3 0

1 year ago