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3 years ago

Can someone show me how to write the standard form of the line that contains a slope of 2/3 and passes through the point (1, 1)?

Mathematics

1 answer:

8090 [49]3 years ago

3 0

Answer:

$\large\boxed{y=\dfrac{2}{3}x+\dfrac{1}{3}\qquad\text{slope-intercept form}}\\\\\boxed{y-1=\dfrac{2}{3}x-\dfrac{2}{3}\qquad\text{point-slope form}}\\\\\boxed{2x-3y=-1\qquad\text{standard form}}$

Step-by-step explanation:

$\text{The standard form:}\ Ax+By=C$

$\text{The point-slope form:}\\\\y-y_1=m(x-x_1)\\\\m-slope\\\\\text{We have the slope}\ m=\dfrac{2}{3}\ \text{and the point}\ (1,\ 1).\ \text{Substitute:}\\\\\underline{y-1=\dfrac{2}{3}(x-1)}\qquad\text{use the distributive property}\\\\y-1=\dfrac{2}{3}x-\dfrac{2}{3}\qquad\text{add 1 to both sides}\\\\\underline{y=\dfrac{2}{3}x+\dfrac{1}{3}}$

$y=\dfrac{2}{3}x+\dfrac{1}{3}\qquad\text{multiply both sides by 3}\\\\3y=2x+1\qquad\text{subtract 2x from both sides}\\\\-2x+3y=1\qquad\text{change the signs}\\\\\underline{2x-3y=-1}$

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If two rectangles have the same area what do u know abt the measures of their sides

kakasveta [241]

In rectangle ABCD
AB * AC = area

In another rectangle WXYZ
WX * WY = area

The sides must be equal or have same multiples and should be divisible by each other

8 0

3 years ago

Ms. Peters drove from her home to the park

worty [1.4K]

It takes 15 minutes for Ms. Peter to drive from park to her home

Given :

from her home to the park at an average speed of 30 miles per hour and

returned home along the same route at an average speed of 40 miles per hour

it takes 20 minutes to travel

Convert 20 minutes in to hour (divide by 60)

20 minutes = 1/3 hour

We know that distance = speed x time

From home to park, distance = $speed \cdot time =30 \cdot \frac{1}{3} =10 miles$

So , distance between home and park is 10 miles

Now we calculate the time taken to return from park to home

$time taken =\frac{distance}{speed} =\frac{10}{40}=\frac{1}{4}\\$

Time taken is 1/4 hours. Convert it into minutes by multiplying by 60

$\frac{1}{4} \cdot 60=15$

So it takes 15 minutes for Ms. Peter to drive from park to her home

Learn more : brainly.com/question/18839247

5 0

3 years ago

Kristin owns a bakery called Kristin’s cakes and n’ such and is considering lowering the price of her cakes. Kristen polls her c

den301095 [7]

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3 years ago

Read 2 more answers

Drag each tile to the correct box. Vector t, with a magnitude of 4 meters/second and a direction angle of 60°, represents a swim

astraxan [27]

Answer:

From top to bottom, the boxes shown are number 3, 5, 6, 2, 4, 1 when put in ascending order.

Step-by-step explanation:

It is convenient to let a calculator or spreadsheet tell you the magnitude of the sum. For a problem such as this, it is even more convenient to let the calculator give you all the answers at once.

The TI-84 image shows the calculation for a list of vectors being added to 4∠60°. The magnitudes of the sums (rounded to 2 decimal places—enough accuracy to put them in order) are ...

... ║4∠60° + 3∠120°║≈6.08

... ║4∠60° + 4.5∠135°║≈6.75

... ║4∠60° + 4∠45°║≈7.93

... ║4∠60° + 6∠210°║≈3.23

... ║4∠60° + 5∠330°║≈6.40

... ║4∠60° + 7∠240°║≈ 3

_____

In the calculator working, the variable D has the value π/180. It converts degrees to radians so the calculation will work properly. The abs( ) function gives the magnitude of a complex number.

On this calculator, it is convenient to treat vectors as complex numbers. Other calculators can deal with vectors directly

_____

<em>Doing it by hand</em>

Perhaps the most straigtforward way to add vectors is to convert them to a representation in rectangular coordinates. For some magnitude M and angle A, the rectangular coordinates are (M·cos(A), M·sin(A)). For this problem, you would convert each of the vectors in the boxes to rectangular coordinates, and add the rectangular coordinates of vector t.

For example, the first vector would be ...

3∠120° ⇒(3·cos(120°), 3·sin(120°)) ≈ (-1.500, 2.598)

Adding this to 4∠60° ⇒ (4·cos(60°), 4°sin(60°)) ≈ (2.000, 3.464) gives

... 3∠120° + 4∠60° ≈ (0.5, 6.062)

The magnitude of this is given by the Pythagorean theorem:

... M = √(0.5² +6.062²) ≈ 6.08

___

<em>Using the law of cosines</em>

The law of cosines can also be used to find the magnitude of the sum. When using this method, it is often helpful to draw a diagram to help you find the angle between the vectors.

When 3∠120° is added to the end of 4∠60°, the angle between them is 120°. Then the law of cosines tells you the magnitude of the sum is ...

... M² = 4² + 3² -2·4·3·cos(120°) = 25-24·cos(120°) = 37

... M = √37 ≈ 6.08 . . . . as in the other calculations.

4 0

3 years ago

Let X and Y be discrete random variables. Let E[X] and var[X] be the expected value and variance, respectively, of a random vari

Ulleksa [173]

Answer:

(a) $E[X+Y]=E[X]+E[Y]$

(b) $Var(X+Y)=Var(X)+Var(Y)$

Step-by-step explanation:

Let X and Y be discrete random variables and E(X) and Var(X) are the Expected Values and Variance of X respectively.

(a)We want to show that E[X + Y ] = E[X] + E[Y ].

When we have two random variables instead of one, we consider their joint distribution function.

For a function f(X,Y) of discrete variables X and Y, we can define

$E[f(X,Y)]=\sum_{x,y}f(x,y)\cdot P(X=x, Y=y).$

Since f(X,Y)=X+Y

$E[X+Y]=\sum_{x,y}(x+y)P(X=x,Y=y)\\=\sum_{x,y}xP(X=x,Y=y)+\sum_{x,y}yP(X=x,Y=y).$

Let us look at the first of these sums.

$\sum_{x,y}xP(X=x,Y=y)\\=\sum_{x}x\sum_{y}P(X=x,Y=y)\\\text{Taking Marginal distribution of x}\\=\sum_{x}xP(X=x)=E[X].$

Similarly,

$\sum_{x,y}yP(X=x,Y=y)\\=\sum_{y}y\sum_{x}P(X=x,Y=y)\\\text{Taking Marginal distribution of y}\\=\sum_{y}yP(Y=y)=E[Y].$

Combining these two gives the formula:

$\sum_{x,y}xP(X=x,Y=y)+\sum_{x,y}yP(X=x,Y=y) =E(X)+E(Y)$

Therefore:

$E[X+Y]=E[X]+E[Y] \text{ as required.}$

(b)We want to show that if X and Y are independent random variables, then:

$Var(X+Y)=Var(X)+Var(Y)$

By definition of Variance, we have that:

$Var(X+Y)=E(X+Y-E[X+Y]^2)$

$=E[(X-\mu_X +Y- \mu_Y)^2]\\=E[(X-\mu_X)^2 +(Y- \mu_Y)^2+2(X-\mu_X)(Y- \mu_Y)]\\$Since we have shown that expectation is linear$\\=E(X-\mu_X)^2 +E(Y- \mu_Y)^2+2E(X-\mu_X)(Y- \mu_Y)]\\=E[(X-E(X)]^2 +E[Y- E(Y)]^2+2Cov (X,Y)$

Since X and Y are independent, Cov(X,Y)=0

$=Var(X)+Var(Y)$

Therefore as required:

$Var(X+Y)=Var(X)+Var(Y)$

7 0

3 years ago