Part 3: Choose a proof method​

Answer:

The answer is option B

Step-by-step explanation:

To find the coefficient of the third term in

[tex](x + 5)^{7} [/tex]

Rewrite the expansion in the form

[tex](a + x)^{n} [/tex]

where n is the index

So we have

[tex] ({5 + x})^{7} [/tex]

After that we use the formula

[tex]nCr( {a}^{n - r} ) {x}^{r} [/tex]

where r is the term we are looking for

For the third term we are looking for the term containing x²

that's

r + 1 = 3

r = 2

So to find the coefficient of the third term

We have

[tex]7C2[/tex]

Hope this helps you

first of all, the notation is wrong it should be [tex] {}^nC_r \text{ and more usual notation is } {n \choose k} [/tex]

second, the

[tex](r+1)^{\text{th}} \text{ term } T_{r+1} \text{ in the expansion of } (x+a)^n \text{ is } {n \choose r}x^{(n-r)}a^r[/tex]

here [tex] a=5 \text{ and } n=7 \text{ and for } 3^{\text{rd}} \text{ term } T_3, \quad r+1=3 \implies r=2 [/tex]

so the coefficient of third term is, [tex]{7 \choose 2}={7\choose 5}[/tex]

an important property of binomial coefficient you should know:

[tex] {n \choose k}={n \choose {n-k}}[/tex]

and if you interchange [tex] x \text{ and } a[/tex]

only the "order" will get reversed. i.e. the series will start from back.

another thing, the [tex] k^{\text{th}} \text{ term from beginning, is the } (n-k+2)^{\text{th}} \text{ term from behind}[/tex]

the graph has 12 segments so angle enclosed by each segment is [tex] {2\pi\over 12}=\frac{\pi}6[/tex]

anti-clockwise is taken as positive, so if you want positive q, you need to rotate 8 segments [tex] q=8\frac,{\pi}6=\frac{4\pi}3 [/tex] , and and 8 circles or units so r=8

and for a negative angle, you need to rotate clockwise

Which is 4 segments from the horizontal line. so [tex]q=-\frac{2\pi}3[/tex] and r will be same, 8 units.

[not sure about -r so I won't include it in answer]

Answer:

Points : ( 8, - 2π/3 ), ( - 8, π/3 ), ( - 8, - 5π/3 )

Step-by-step explanation:

For the first two cases, ( r, θ ) r would be > 0, where r is the directed distance from the pole, and theta is the directed angle from the positive x - axis.

So when r is positive, we can tell that this point is 8 units from the pole, so r is going to be 8 in either case,

( 8, 240° ) - because r is positive, theta would have to be an angle with which it's terminal side passes through this point. As you can see that would be 2 / 3rd of 90 degrees more than a 180 degree angle,or 60 + 180 = 240 degrees.

( 8, - 120° ) - now theta will be the negative side of 360 - 240, or in other words - 120

Now let's consider the second two cases, where r is < 0. Of course the point will still be 8 units from the pole. Again for r < 0 the point will lay on the ray pointing in the opposite direction of the terminal side of theta.

( - 8, 60° ) - theta will now be 2 / 3rd of 90 degrees, or 60 degrees, for - r. Respectively the remaining degrees will be negative, 360 - 60 = 300, - 300. Thus our second point for - r will be ( - 8, - 300° )

_________________________________

So we have the points ( 8, 240° ), ( 8, - 120° ), ( - 8, 60° ), and ( - 8, - 300° ). However we only want 3 cases, so we have points ( 8, - 120° ), ( - 8, 60° ), and ( - 8, - 300° ). Let's convert the degrees into radians,

Points : ( 8, - 2π/3 ), ( - 8, π/3 ), ( - 8, - 5π/3 )

Answer:

  no

Step-by-step explanation:

If any x-value is repeated, the relation is not a function. Both x=4 and x=9 are repeated values, so this relation is not a function.

Answer:

Step-by-step explanation:

Hello, please consider the following.

For x > 1, we can apply Pythagoras theorem as below.

[tex]\text{Let's estimate this sum of two squares.} \\\\(2x)^2+(x^2-1)^2=4x^2+x^4-2x^2+1=x^4+2x^2+1\\\\\text{Let's estimate this square, now.} \\\\(x^2+1)^2=x^4+2x^2+1\\\\\text{The two expressions are equal, meaning.} \\\\(2x)^2+(x^2-1)^2=(x^2+1)^2\\\\\text{Using Pythagoras' theorem, we can say that this is a right triangle.}[/tex]

Thank you

Answer:

Three points are (0,-5.5), (-1,-3), (-2.2,0) and graph is shown below.

Step-by-step explanation:

The given equation is

[tex]-2y=5x+11[/tex]

We need to find three points that solve the equation.

Put x=0,

[tex]-2y=5(0)+11[/tex]

[tex]-2y=11[/tex]

[tex]y=-5.5[/tex]

Put x=-1,

[tex]-2y=5(-1)+11[/tex]

[tex]-2y=6[/tex]

[tex]y=-3[/tex]

Put y=0,

[tex]-2(0)=5x+11[/tex]

[tex]5x=-11[/tex]

[tex]x=-2.2[/tex]

So, three points (0,-5.5), (-1,-3) and (-2.2,0) are the solutions of the given equation.

Plot these points on a coordinate plane and connect them by a straight line as shown below.

Answer:

  [tex]\dfrac{3}{(y+2)^3}[/tex]

Step-by-step explanation:

Maybe you want this written using math symbols. It will be ...

  [tex]\boxed{\dfrac{3}{(y+2)^3}}[/tex]

Answer:

[tex] \frac{11x}{3y} [/tex]

Step-by-step explanation:

[tex] \frac{7x}{3y} + \frac{12x}{9y} [/tex]

Make both a single fraction by adding together.

[tex] \frac{3(7x) + 1(12x)}{9y} [/tex]

[tex] \frac{21x + 12x}{9y} [/tex]

[tex] \frac{33x}{9y} [/tex]

Simplify

[tex] \frac{3(11)x}{3(3y)} [/tex]

[tex] \frac{11x}{3y} [/tex]

We have 26 letters and 3 slots to fill. We can reuse a letter if it has been picked, so we have 26^3 = 26*26*26 = 17,576 different three letter "words". I put that in quotes because a lot of the words aren't actual words, but more just a sequence of letters.

Answer:

The survey result doesn't indicate the change

Step-by-step explanation:

Previous study result is 50%

Survey result:

Comparing with previous result:

Since this result is within 5% level of significance, it can be concluded that the survey result doesn't indicate the change

━━━━━━━☆☆━━━━━━━

▹ Answer

(-39/35, 9/7)

▹ Step-by-Step Explanation

5y + 2y = 9

-5x - 2y = 3

Solve the equation:

y = 9/7

-5x - 2y = 3

Substitute the value of y:

-5x - 2 * 9/7 = 3

x = -39/35

(x, y) = (-39/35, 9/7)

Hope this helps!

CloutAnswers ❁

━━━━━━━☆☆━━━━━━━

To solve this system by addition, we start by adding both of our equations together but notice that the x terms and the y terms cancel out.

This leaves us with 0 on the left side and on the right side,

9 + 13 = 12 so we are left with the equation 0 = 12.

Since 0 = 12 is a false statement, this means that

there is no solution to our system of equations.

Answer:

BC = 13.4

Step-by-step explanation:

its a law of cosines S-A-S

a² = b² + c² - 2bc cosA

a² = 12.6² + 4.6² - ( 2 * 12.6 * 4.6 * cos 90 )

a² = 179.92

a = sqrt (179.92)

a = 13.4

The triangle (call it T ) has base and height 4, so its area is 1/2*4*4 = 8. Then the joint density function is

[tex]f_{X,Y}(x,y)=\begin{cases}\frac18&\text{for }(x,y)\in T\\0&\text{otherwise}\end{cases}[/tex]

where T is the set

[tex]T=\{(x,y)\mid 0\le x\le4\land0\le y\le4-x\}[/tex]

(a) I've attached an image of the integration region.

[tex]P(X<3,Y<3)=\displaystyle\int_0^1\int_0^3f_{X,Y}(x,y)\,\mathrm dy\,\mathrm dx+\int_1^3\int_0^{4-x}f_{X,Y}(x,y)\,\mathrm dy\,\mathrm dx=\frac12[/tex]

(b) X and Y are independent if the joint distribution is equal to the product of their marginal distributions.

Get the marginal distributions of one random variable by integrating the joint density over all values of the other variable:

[tex]f_X(x)=\displaystyle\int_{-\infty}^\infty f_{X,Y}(x,y)\,\mathrm dy=\int_0^{4-x}\frac{\mathrm dy}8=\begin{cases}\frac{4-x}8&\text{for }0\le x\le4\\0&\text{otherwise}\end{cases}[/tex]

[tex]f_Y(y)=\displaystyle\int_{-\infty}^\infty f_{X,Y}(x,y)\,\mathrm dx=\int_0^{4-y}\frac{\mathrm dx}8=\begin{cases}\frac{4-y}8&\text{for }0\le y\le4\\0&\text{otherwise}\end{cases}[/tex]

Clearly, [tex]f_{X,Y}(x,y)\neq f_X(x)f_Y(y)[/tex], so they are not independent.

Answer:

A. -11

Step-by-step explanation:

In the function, replace x with -2

R(x) = x^2 - 3x - 1 ➡ R(-2) = (-2)^2 - 3 × 2 -1 = -11

Answer:

Look at that picture

Step-by-step explanation:

Answer:

7.5 < x≤10.5

Step-by-step explanation:

14<2x−1≤20

Add 1 to all sides

14+1<2x−1+1≤20+1

15<2x≤21

Divide each side by 2

15/2 <2x/2 ≤21/2

7.5 < x≤10.5

Steps to solve:

14 < 2x - 1 <= 20

~Add 1 to everything

15 < 2x <= 21

~Divide 2 to everything

7.5 < x <= 10.5

Best of Luck!

Answer:

different

Step-by-step explanation:

reflection is basically like a mirror where it reflects you. rotation is when an object spins/rotates.

Step-by-step explanation:

Hi, there!!!

According to the question we must find the area of shaded region, but we must find area of circle and rectangle to find area of shaded region,

So, let's simply work with it,

Firstly, finding the area of rectangle,

length = 11cm.

breadth = 11cm.

now, area= length× breadth.

or, a = 11cm× 11cm.

a= 121cm^2

Now, let's work out the area of circle.

radius= 5cm

and pi. = 3.14 {using pi value as 3.14}

now,

area of a circle = pi× r^2

or, a= 3.14×5^2

or, a = 78.5 cm^2.

Therefore, The area of a circle is 78.5cm^2.

Now lastly finding the area of shadedregion,

area of shaded region = area of rectangle - area of circle.

or, area of shaded region = 121cm^2 - 78.5cm^2

Therefore, the area of shaded region is 42.5 cm^2.

Hope it helps...

Answer:

0.03 square meters

Step-by-step explanation:

1. convert 20 cm, 15 cm into m by dividing the number by 100 then you got 0.2 m and 0.15 m respectively

2. calculate the area by multiply 2 numbers together

0.2 × 0.15 = 0.03 square meter

Answer:

L = 29,550 mm

Step-by-step explanation:

i think i've done this before.. but anyway Lets make it simple and easy.

Let A = 600mm

Let B = 300mm

Let C = 16 as number turns

Let d = 20mm

L = sqrt ((3.14 * (600 - 20))² + 300³)    * 16

L = 29,550 mm

Answer:

x = sqrt(50) = 5sqrt(2) = 7.071 ft (to 3 decimals)

Step-by-step explanation:

referring to the diagram

theta (x) = atan(10/x) - atan(5/x)

differentiate with respect to x

theta'(x) = 5/(x^2+25) - 10/(x^2+100)

For x to have an extremum (max. or min)

theta'(x) = 0  ="

5/(x^2+25) - 10/(x^2+100) = 0

transpose and cross multiply

10(x^2+25) -5(x^2+100) = 0

expand and simplify

10x^2+250 - 5x^2-500 = 0

5x^2 = 250

x^2=50

x = sqrt(50) = 5sqrt(2) = 7.071 ft (to 3 decimals)

Since we know that if x becomes large, theta will decrease, so

x = 5sqrt(2) is a maximum.

Answer:

Although the question is not clear, It most likely looks like you were asking for the calculation of the savings for the month after increase.

savings for the month after increase = $1172.4

Step-by-step explanation:

First, let us calculate how much was saved before the increase in savings:

monthly income = $19,540

Percentage saved = 4% of monthly income

= 4/100 × 19,540 = 0.04 × 19,540 = $781.6

Next, we are given the ratio of increase in savings as 3:2

Let the new savings amount be x

3 : 2 = x : 781.6

[tex]\frac{3}{2} = \frac{x}{781.6} \\781.6\ \times 3\ =2x\\2344.8 = 2x\\x =\frac{2344.8}{2} \\x = \$1172.4[/tex]

therefore savings for the month after increase = $1172.4

Just incase you were looking for the savings before the increase, the answer is $781.6 (as calculated above)

Answer:

x< -3 and 0 < x < 4

Step-by-step explanation:

x^3 – x² <12x​

Subtract 12x from each side

x^3 -x^2 - 12x< 0

Factor

x( x^2 -x-12) <0

Factor

x( x-4) ( x+3) < 0

Using the zero product property

x=0   x=4  x=-3

We have to check the signs regions

x < -3

-( -) (-) < 0   True

-3 to 0

-( -) (+) < 0   False

0 to 4

+( -) (+) < 0   True

x>4

+( +) (+) < 0   False

The regions this is valid is

x< -3 and 0 < x < 4

Answer:

If the width of the compass changed, it would make the arc smaller or larger. This would then make the line segment to be drawn smaller or larger, so it would not match the original.

Step-by-step explanation:

We assume your construction is trying to copy the length of a line segment. That length is "measured" by the width of the compass. If it is changed, it no longer matches the length of the segment you're trying to copy, so you will not get the copy you want.

Answer:

$25

Step-by-step explanation:

.5 * 50 = 25

25<27.5<30

The cheapest supplier is the first one.

Answer:

3780.  

Step-by-step explanation:

To solve this we will start by just considering the number of ways to arrange 9 objects. We can do this in  9!  ways.

However since we have 3 reoccurring letters in Tennessee namely n,s and e we need to remove the times these form the same arrangement. Let me give an example to show what this means. Lets say we have the arrangement:

ennetssee

Now what happens if we exchange the places of the letters n for example? Of course we get the same arrangement of letters. We don’t want to count these as 2 different arrangements since for our interests they are the same. We therefore divide  9!  by the number of times this type of double counting occurs.

Since the word has the letter n occurring twice we will start by diving by  2! .

The letter s occurs 2 times as well so we will have to divide by  2!  again.

Finally the letter e occurs 4 times and so we will have to divide by  4!  here.

Now we get the following result:

9/(2 x 2 x 4)=3780.  

So in conclusion there are 3780 different ways to arrange the letters in Tennessee.

Answer:

15

Step-by-step explanation:

Just find out the pattern.  It is decreasing, so let's find out how much it is decreasing by.

31-29= -2

29-24= -5

24-22= -2

22-17= -5

The pattern is -2, -5, -2, -5... So the next one should be -2 again!  17-2=15.

Remember, a pattern doesn't always have to be subtracting, adding, dividing, or multiplying at a constant number!  It can switch between two, like this problem!

Answer:

work pictured and shown

Answer:

Last one

Step-by-step explanation:

● [ ( 3^2 × 5^0) / 4 ]^2

5^0 is 1 since any number that has a null power is equal to 1.

●[ (3^2 ×1 ) / 4 ]^2

● (9/4)^2

● 81 / 16

Answer:

3* 10 ^12

Step-by-step explanation:

(5x10^7)(6x10^4)

Multiply the numbers together

5*6 =30

Add the exponents

10^7 * 10 ^ 4 = 10 ^(7+4) = 10 ^11

30 * 10 ^11

But this is not scientific notation since 30 >10

Move the decimal one place to the left and add 1 to the exponent

3* 10 ^12

Answer:

3* 10 ^12

Step-by-step explanation:

Answer:

Step-by-step explanation:

A school bag contains 12 pens of which 5 are red and the other are black. 4 pens are selected from the bag.

(a) How many different samples of size 4 pens are possible?

12C4=12!/(4!*8!)=495

(b) How many samples have 3 red pens and 1 black pen?

5C3*7C1

5C3=5!/(3!*2!)=10

7C1=7!/(1!*6!)=7

=>5C3*7C1=10*7=70

(c) How many samples of size 4 contain at least two red pens?

(5C2*7C2)+(5C3*7C1)+(5C4*7C0)

5C2=5!/(2!*3!)=10

7C2=7!/(2!*5!)=21

5C3=5!/(3!*2!)=10

7C1=7!/(1!*6!)=7

5C4=5!/(4!*1!)=5

7C0=7!/(0!*7!)=1

=>(5C2*7C2)+(5C3*7C1)+(5C4*7C0)=285

(d) How many samples of size 4 contain at most one black pen?

(7C1*5C3)+(7C0*5C4)

7C1=7!/(1!*6!)=7

7C0=7!/(0!*7!)=1

5C3=5!/(3!*2!)=10

5C4=5!/(4!*1!)=5

=>(7C1*5C3)+(7C0*5C4)=(7*10)+(1*5)=75

Answer:

seeed

Step-by-step] explanation:

ddd~!`