the set of all upper triangular n x n matrices is a subspace w of mnxn(f) (see exercise 12 of section 1.3). find a basis for w. vvhat is the dimension of w?

The explicit solution of the given differential equation is [tex]& y=[c(1+\sqrt{x})-1]^2[/tex]

Solution of the Differential Equation :

Any equation with one or more terms and one or more derivatives of the dependent variable with respect to the independent variable is referred to as a differential equation (i.e., independent variable)

We employ the approach of variable separation to discover the answer to the differential equation. By splitting the equation into two halves, we can find a solution. We integrate both sides after moving all of the equations involving the y variable to one side and all of the equations involving the x variable to the other side.

⇒[tex](\sqrt{x}+x) \frac{d y}{d x} & =(\sqrt{y}+y) \\[/tex]

⇒[tex]\frac{d y}{\sqrt{y}(1+\sqrt{y})} & =\frac{d x}{\sqrt{x}(1+\sqrt{x})}[/tex]

Put [tex]$\sqrt{y}=u \quad \sqrt{x}=v$[/tex]

⇒[tex]& \frac{1}{2 \sqrt{y}} d y=d u \frac{1}{2 \sqrt{x}} d x=d v \\[/tex]

⇒[tex]& \frac{d y}{\sqrt{y}}=2 d u \frac{d x}{\sqrt{x}}=2 d v[/tex]

By substituting,

⇒[tex]& \int \frac{7 d u}{1+u}=\int \frac{2 d v}{1+v} \\[/tex]

⇒[tex]& \ln (1+u)=\ln (1+v)+\ln c \\[/tex]

⇒[tex]& \ln (1+u)=\ln [c(1+v)] \\[/tex]

⇒[tex]& (1+u)=c(1+v) \\[/tex]

⇒[tex]& (1+\sqrt{y})=c(1+\sqrt{x}) \\[/tex]

⇒[tex]& \sqrt{y}=c(1+\sqrt{x})-1 \\[/tex]

⇒[tex]& y=[c(1+\sqrt{x})-1]^2[/tex]

Therefore, the explicit solution of the given differential equation is [tex]& y=[c(1+\sqrt{x})-1]^2[/tex]

For more such questions on differential equation

https://brainly.com/question/2273154

#SPJ4

The transformed function is g ( x ) = ( -1/2 ) | x - 1 | + 2

The transformation of a function may involve any change.

Usually, these can be shifted horizontally (by transforming inputs) or vertically (by transforming output), stretched (multiplying outputs or inputs), etc.

If the original function is y = f(x), assuming the horizontal axis is the input axis and the vertical is for outputs, then:

Horizontal shift (also called phase shift):

Left shift by c units: y=f(x+c) (same output, but c units earlier)

Right shift by c units: y=f(x-c)(same output, but c units late)

Vertical shift:

Up by d units: y = f(x) + d

Down by d units: y = f(x) - d

Stretching:

Vertical stretch by a factor k: y = k × f(x)

Horizontal stretch by a factor k: y = f(x/k)

Given data ,

Let the parent function be represented a f ( x )

Now , the value of f ( x ) = | x |

Let the function be plotted on the graph and

when the function is transformed by a reflection on y axis , we get

h ( x ) = - | x |

Let the function be shifted left by 1 unit , we get

h' ( x ) = - | x - 1 |

Now , when the function is transformed by a vertical stretch of ( 1/2 ) units , we get

j ( x ) = - ( 1/2 ) | x - 1 |

Now , when the function is shifted vertically up by 2 units , we get

g ( x ) = ( -1/2 ) | x - 1 | + 2

Hence , the transformed function is g ( x ) = ( -1/2 ) | x - 1 | + 2 and it is plotted

To learn more about transformation of functions click :

https://brainly.com/question/26896273

#SPJ1

(7+3/2)^3

Answer: 614.125

To round to the nearest whole number it would be 614

hope this helped =)

x=-1/2 and  x=-3 are the zeros of the function y =2x²+7x+3

A quadratic equation is a second-order polynomial equation in a single variable x , ax²+bx+c=0. with a ≠ 0 .

The given function is y= 2x²+7x+3

Factor out the equation

2x²+6x+x+3

2x(x+3)+(x+3)

(2x+1)(x+3)=0

So the roots we get

2x+1=0

x=-1/2 is one  zero and x=-3 is another zero.

Hence, x=-1/2 and  x=-3 are the zeros of the function y =2x²+7x+3

To learn more on Quadratic equation click:

https://brainly.com/question/17177510

#SPJ1

The expected value of cream-filled donuts the store City Donuts is selling should be 2.

We are aware of In the realm of probability theory, the expected value, commonly referred to as the expected average, is a generalization of the weighted average.

Given, City Donuts recently sold 14 donuts, of which 4 were cream-filled donuts.

So, The probability of cream-filled donuts is = 4/14 = 2/7.

Therefore, The expected number of cream-filled donuts is,

= (2/7)×7.

= 2.

learn more about expected value here :

https://brainly.com/question/29574962

#SPJ9

The Cartesian Equation of the given parametric equation is written below

: x^2 + y^2=4

To eliminate the parameter t and find the Cartesian equation, we can use the trigonometric identity: cos^2(t) + sin^2(t) = 1. We can rearrange the given equations to get:

x(t) = 2cos(t)

y(t) = 2sin(t)

Dividing both sides of each equation by 2, we get:

cos(t) = x/2

sin(t) = y/2

Squaring both equations and adding them, we get:

cos^2(t) + sin^2(t) = (x/2)^2 + (y/2)^2

Using the identity, we can simplify the right-hand side to get:

1 = (x/2)^2 + (y/2)^2

Multiplying both sides by 4, we get the Cartesian equation:

x^2 + y^2 = 4

This is the equation of a circle with radius 2 centered at the origin. The domain of this equation is all real numbers, and the range is from -2 to 2 (inclusive) in both the x and y directions, represented as [-2,2].

In summary, the Cartesian equation of the given parametric equations is x^2 + y^2 = 4, with domain of all real numbers and range of [-2,2].

To know more about Parametric Equation visit:

https://brainly.com/question/28537985

#SPJ4

A system may or may not be:

a.) Memoryless: Yes, Time Invariant: Yes, Linear: Yes, Casual: No, Stable: Yes

b.) Memoryless: No, Time Invariant: No, Linear: No, Casual: No, Stable: Yes

c.) Memoryless: No, Time Invariant: No, Linear: No, Casual: Yes, Stable: Yes

d.) Memoryless: Yes, Time Invariant: No, Linear: No, Casual: No, Stable: Yes

e.) Memoryless: Yes, Time Invariant: No, Linear: No, Casual: No, Stable: Yes

f.) Memoryless: No, Time Invariant: Yes, Linear: Yes, Casual: No, Stable: Yes

g.) Memoryless: Yes, Time Invariant: Yes, Linear: No, Casual: Yes, Stable: Yes

A memoryless, time invariant, linear, casual, and stable system is an idealized system in which the output is directly proportional to the input and the output at any given time is independent of the outputs at any other time.

The system is stable in the sense that the output does not grow indefinitely as the input increases, and it is casual in the sense that the output at any given time is only affected by the inputs at previous times.

To learn more about linear system link is here

brainly.com/question/21404414

#SPJ4

16 cookies were oatmeal

How long do cookies with oats last? The cookies can last up to two weeks when kept in an airtight container. The cookies may be frozen and kept for two months. But, these cookies taste best when they are still warm from the oven!

Keep crisp cakes in a jar with such a loose-fitting cover for cookies which will be consumed within a day or two; keep soft sweets in a jar with a close cover. Wax paper should be placed between the layers of cookies that are exceptionally soft, delicate, iced, or adorned. Many cookies may be frozen.

To find the number of oatmeal cookies, take the total number of cookies and multiply by the fraction that were oatmeal

24 * 2/3 = 48/3 = 16

16 cookies were oatmeal

To know more about find the number of oatmeal cookies visit:

https://brainly.com/question/12195026

#SPJ1

The value of x in this figure is equal to: D. 5.

In Mathematics and Geometry, the sum of the interior angles of both a regular and irregular polygon is given by this formula:

Sum of interior angles = 180 × (n - 2)

Note: The given geometric figure (regular polygon) represents a pentagon and it has 5 sides.

Sum of interior angles = 180 × (5 - 2)

Sum of interior angles = 180 × 3

Sum of interior angles = 540°.

112 + 7x + 5 + 6x + 2 + 10x - 8 + 4x + 24 = 540°.

27x = 135

x = 135/27

x = 5.

Read more on sum of interior angles here: brainly.com/question/13293407

#SPJ1

Answer:

the logistic function that models the population of this species as a function of time is P(t) = 7000 / (1 + 0.05 * e^(-0.1682 * t)).

Step-by-step explanation:

We can use the logistic growth equation to model the population of this species as a function of time:

P(t) = K / (1 + A * e^(-r * t))

Where:

P(t) is the population at time t

K is the carrying capacity of the environment

A is the initial population as a proportion of the carrying capacity (A = P(0)/K)

r is the growth rate of the population

We are given that the initial population A is 350/7000 = 0.05 (since the carrying capacity is 7000). We are also given that after 5 years the population has grown to 900. So we can use this information to find the growth rate r:

P(5) = 900 = K / (1 + A * e^(-r * 5))

We also know that the carrying capacity K is 7000. Substituting these values, we get:

900 = 7000 / (1 + 0.05 * e^(-r * 5))

Multiplying both sides by the denominator and simplifying, we get:

1 + 0.05 * e^(-r * 5) = 7.777...

Subtracting 1 from both sides, we get:

0.05 * e^(-r * 5) = 6.777...

Dividing both sides by 0.05, we get:

e^(-r * 5) = 135.555...

Taking the natural logarithm of both sides, we get:

-ln(135.555...) = -r * 5

Solving for r, we get:

r = 0.1682...

Now that we have the growth rate r, we can use the logistic growth equation to find the function that models the population as a function of time:

P(t) = 7000 / (1 + 0.05 * e^(-0.1682 * t))

Therefore, the logistic function that models the population of this species as a function of time is P(t) = 7000 / (1 + 0.05 * e^(-0.1682 * t)).

By applying the unitary method, counting 67 colonies on a plate with 1ml of the 1:1,000,000 dilution indicates that 67,000,000 bacteria were present in 1ml of the original sample.

The unitary method is a mathematical technique that involves finding a unit value and using it to solve problems. In this case, we need to determine the number of bacteria present in 1ml of the original sample.

The dilution factor represents the ratio of the volume of the original sample to the volume of the diluted sample. In this case, the dilution factor is 1:1,000,000, which means that 1ml of the original sample was diluted with 1,000,000ml of a diluent solution to obtain 1ml of the diluted sample. Therefore, the number of bacteria in the original sample is 1,000,000 times the number of bacteria in the diluted sample.

Now, let's use the colony count to determine the number of bacteria in the diluted sample. We are told that 67 colonies were counted on the plate with 1ml of the 1:1,000,000 dilution. This means that each colony represents the growth of a single bacterium in the diluted sample. Therefore, the number of bacteria in the diluted sample is 67.

Using the unitary method, we can now determine the number of bacteria in 1ml of the original sample. We know that the number of bacteria in the original sample is 1,000,000 times the number of bacteria in the diluted sample. Therefore:

Number of bacteria in original sample = Dilution factor x Number of bacteria in diluted sample

Number of bacteria in original sample = 1,000,000 x 67

Number of bacteria in original sample = 67,000,000

So, the answer is that 67,000,000 bacteria were present in 1ml of the original sample.

To know more about unitary method here.

https://brainly.com/question/28276953

#SPJ4

The solution of the system of equations is c = 10 and d = 7.

One or many equations having the same number of unknowns that can be solved simultaneously are called simultaneous equations. And the simultaneous equation is the system of equations.

Given:

A system of equations,

c+d=17  {equation 1}

c-d=-3  {equation 2}

Adding both the equation,

we get,

c + d + c - d = 17 + 3

2c = 20

Divide by 2,

we get,

c = 10 and d = 7.

Therefore, c = 10 and d = 7.

To learn more about the system of equations;

brainly.com/question/13729904

#SPJ1

Answer: x = 41

Step-by-step explanation:

When you add supplementary angles together, you should have a total of 180 degrees. You can set up and equation like this...

(2x - 25) + 3x = 180

Combine like terms.   5x - 25 = 180

Add 25 to both sides to help isolate x     5x = 205

Divide by 5 to both sides to get x by itself.   x = 41

A variable can be both Nominal and ordinal as shown in the explanation below.

Nominal data is defined as data that's used for naming or labeling variables, without any quantitative value. It's occasionally called “ named ” data – a meaning chased from the word nominal.

Ordinal data is a type of categorical data with an order. The variables in ordinal data are listed in an ordered manner. The ordinal variables are generally numbered, so as to indicate the order of the list.

Age can be both nominal and ordinal data depending on the question types. I.e “ How old are you ” is used to collect nominal data while “ Are you the firstborn or What position are you in your family ” is used to collect ordinal data.

An interval variable is analogous to an ordinal variable, except that the intervals between the values of the numerical variable are inversely spaced.

A categorical variable( occasionally called a nominal variable) is one that has two or further orders, but there's no natural ordering to the orders.

separate variables are innumerable in a finite quantum of time. For illustration, you can count the change in your fund. You can count the plutocrat in your bank account. You could also count the quantum of plutocrat in everyone’s bank accounts. It might take you a long time to count that last item, but the point is it’s still innumerable.

Learn more about Variables:

https://brainly.com/question/18763328

#SPJ4

Answer:

108+x=108 or x=108-108

x=72

x+y=108

y=108

x+88-88=108-88

x=92

88+y=88

if my answer is helpful comment

Answer:

Step-by-step explanation:

The statement (i) and (iv) is true.

An equation containing variables with its highest power as one is called linear equation.

The cost of 2 game apps is $3.50; the cost of 5 game apps is $8.75.

The graph below represents the linear relationship.

By the graph, the equation of the graph is y=1.75x

And the point (0,0) lies on the graph.

The points (7.3,6) and (31.75,51) is not on the line.

Hence, the statement (i) and (iv) is true.

Question:

The cost of 2 game apps is $3.50; the cost of 5 game apps is $8.75.The graph below represents this linear relationship. Select all true statements about the graph.

(i) The equation of the graph is y=1.75x.

(ii) The point (7.3,6) lies on the line.

(iii) The point (31.75,51) lies on the line.

(iv) The point (0,0) lies on the line.

Learn more about linear equation here:

https://brainly.com/question/29111179

#SPJ9

The probability of being dealt a flush is 0.001980,  probability of being dealt a one pair is 0.422569,  probability of being dealt two pairs is 0.04753.

a) First select a suit: 4 choices

then, we can have to select 5 cards out of 13:  C(13, 5)

required probability: 4*C(13, 5)/C(52, 5)

= 0.001980

b)- We have to select two cards to make a pair: C(4, 2) choices (we have to select 2 from 4 because a suit can't have 2 cards    of  same number, so we are selecting 2 suits from 4),

then select a number for the pair: 13 choices,

now for remaining three cards: each card can be of same suit but number must be different, i.e. 4³*C(12, 3)

required probability: 13*C(4, 2) * C(12, 3) *4³ / C(52, 5)

= 0.422569

c)- First, we have to select two numbers for two pairs: C(13, 2) ,

Select suits for both pairs: C(4, 2) * C(4, 2) ,

For the remaining one card: 11 choices for the number and 4 choices for the suit,

required probability: C(13, 2)*C(4, 2)*C(4, 2)*11*4/C(52, 5)

= 0.04753

Probability means possibility. It's a branch of mathematics that deals with the circumstance of a arbitrary event. The value is expressed from zero to one. Probability has been introduced in Maths to prognosticate how likely events are to be. The meaning of probability is principally the extent to which commodity is likely to be.

Learn more about Probability:

https://brainly.com/question/13184490

#SPJ4

Complete question:

If it is assumed that all (52 5) poker hands are equally likely, what is the probability of being dealt (a) a flush? (A hand is said to be a flush if all 5 cards are of the same suit.)

(b) one pair? (This occurs when the cards have denominations a, a, b, c, d, wherea, b, c, and d are all distinct.)

(c) two pairs? (This occurs when the cards have denominations a, a, b, b, c, wherea, b, andc are all distinct.)

The triangle ABC has sides of length a = 106.5, b = 126, and c = 162, and angles A = 83.3, B = 43, and C = 53.7. Additionally, we have A₁ = 32.7, A₂ = 32.7, and C₁ = 8.2.

To solve the triangle ABC, we can use the Law of Cosines and the Law of Sines.

First, we can use the Law of Cosines to find the length of side a, which is opposite angle A:

a² = b² + c² - 2bc cos(B)

a² = (126)² + (162)² - 2(126)(162) cos(43)

a = 106.5

Next, we can use the Law of Sines to find angle A:

sin(A) / a = sin(B) / b

sin(A) = (a sin(B)) / b

A = 83.3

To find angle C, we can use the fact that the angles of a triangle add up to 180:

C = 180 - A - B

C = 53.7

Next, we can use the given relationship between angles A₁ and A₂ to find their values:

A₂ = A₁ = 2C₁

A₁ + A₂ + C₁ = 180

A₁ + 2A₁ + A₁/2 = 180

5.5A1₁ = 180

A₁ = 32.7

A₂ = 32.7

C₁= 8.2

Learn more about triangle here: brainly.com/question/17335144

#SPJ4

The total length of the tiles that Chris needs to cover the floor is 63/8 inches.

Multiplication is a method of finding the product of two or more numbers

We need to find the total length of the tiles, we need to multiply the number of tiles by the length of each tile.

The number of tiles Chris needs is 9.

The length of each tile is 7/8 of an inch.

To find the total length of the tiles, we can multiply the number of tiles by the length of each tile as follows:

Total length of tiles = Number of tiles x Length of each tile

Total length of tiles = 9 x (7/8) inches

Total length of tiles = 63/8 inches

Therefore, the total length of the tiles that Chris needs to cover the floor is 63/8 inches.

To learn more on Multiplication click:

https://brainly.com/question/5992872

#SPJ9

Complete question is given below.

Chris needs 9 tiles to cover length of floor, each tile is 7/8 of an inch what is the total length of tiles?

The required minimal sample size would be 26. This is because in order to estimate the mean score with a margin of error of 10 and a confidence level of 90%, the sample size must be large enough for the Central Limit Theorem to apply.  Therefore, in this case, the sample size would be (1.96*100)/10 = 19.6, which is approximately 26.

1. Calculate the sample size, n: n = (1.96*σ)/m

2. Plug in the values: n = (1.96*100)/10

3. Calculate: n = 19.6

4. Round up: n = 26

The required minimal sample size of 26 is necessary in order to estimate the mean SAT score for a population of students with a 90% confidence interval and a margin of error of 10. This is because, in order for the Central Limit Theorem to apply, the sample size must be large enough. The formula for the sample size is (1.96*σ)/m, where σ is the population standard deviation and m is the margin of error. Plugging in the values, we get (1.96*100)/10, which is approximately 19.6. Therefore, the required minimal sample size is 26. This sample size is necessary in order to make sure that the estimates have a high degree of accuracy and reliability.

Learn more about sample size here

https://brainly.com/question/25894237

#SPJ4

Using equations, the time for the main engine 14.4 seconds and 21.6 seconds for the auxiliary engine

Let's call the time each engine takes to consume its allotted fuel supply as "t₁" for the main engine and "t₂" for the auxiliary engine.

From the first piece of information, we know:

t₁ = (2/3)t₂

From the second piece of information, we know that the combined fuel consumption time for both engines is 36 seconds:

t₁ + t₂ = 36

Now we can substitute the first equation into the second:

t₁ + (2/3)t₂ = 36

Combining like terms:

t₂ = 21.6

Finally, substituting t₂ back into the first equation:

t₁ = (2/3)(21.6) = 14.4

So the main engine alone could be fired for 14.4 seconds and the auxiliary engine alone could be fired for 21.6 seconds.

Learn more on equations here;

https://brainly.com/question/18831322

#SPJ1

Answer: 97.5% ( look at the image for the solution )

Step-by-step explanation:

The lines L1 and L2 are not parallel and intersect at a single point. We have also found the point of intersection.

If the direction vectors are parallel, then the lines are parallel. If the direction vectors are not parallel but do not intersect, then the lines are skew. If the direction vectors are not parallel and do intersect, then the lines intersect at a single point.

To determine whether the given lines are parallel, skew, or intersecting, we need to compare their direction vectors. The direction vectors of the lines are the coefficients of the parameters t and s in the respective equations. Thus, the direction vector of L1 is <2,-1,3> and the direction vector of L2 is <4,-2,5>.

To check whether the direction vectors are parallel, we can compute their cross product. If the cross product is the zero vector, then the direction vectors are parallel.

<2,-1,3> × <4,-2,5> = (7,2,-10)

Since the cross product is not zero, the direction vectors are not parallel. Thus, the lines are either skew or intersecting.

To determine whether the lines are intersecting, we can set the parametric equations of the lines equal to each other and solve for t and s. This will give us the point of intersection.

3 + 2t = 1 + 4s

4 - t = 3 - 2s

1 + 3t = 4 + 5s

Rearranging the equations, we get:

2t - 4s = -2

t + 2s = 1

3t - 5s = 3

Using Gaussian elimination or other methods, we can solve for t and s:

t = 11/13

s = 2/13

Substituting these values back into either equation gives us the point of intersection:

x = 3 + 2(11/13) = 37/13

y = 4 - (11/13) = 41/13

z = 1 + 3(11/13) = 40/13

Thus, the lines intersect at the point (37/13, 41/13, 40/13).

To know more about point of intersection here,

https://brainly.com/question/14217061

#SPJ4

Complete Question:

Determine whether the lines L1 and L2 are parallel, skew, or intersecting. If they intersect, find the point of intersection.

L1: x = 3 + 2t, y = 4 – t, z = 1 + 3t

L2: x = 1 + 4s, y = 3 – 2s, z = 4 + 5s

The distance between point D and E is 17.89 units

Distance between two points is the length of the line segment that connects the two points in a plane. The formula to find the distance between the two points is usually given by d=√((x2 – x1)² + (y2 – y1)²). This formula is used to find the distance between any two points on a coordinate plane or x-y plane.

d=√((x2 – x1)² + (y2 – y1)²).

d = √ (11-3)² + 13-(-3)²

d = √ 8²+ 16²

d = √ 64 + 256

d = √320

d = 17.89 units

learn more about distance between two point

https://brainly.com/question/7243416

#SPJ1

The system of equations has only one solution and is the point (1, 1)

Here we have the graph of a system of equations, where we can see that both of them are linear equations.

Whenw e have a graph of a system, the solutions are all the points where the graphs of the equations intercept.

On the given graph, we can see that the two lines intersept at the point (1, 1)

So we have only one solution and is the point (1, 1)

Learn more about systems of equations by reading:

https://brainly.com/question/13729904

#SPJ1

The stores do not form similar rectangles, as the ratios between the equivalent side lengths are different.

Similar polygons are polygons that share these two features presented as follows:

To observe if the rectangles are similar for this problem, we must observe if the side lengths of Store B and of Store A have the same ratio, as follows:

Different ratios, hence not similar.

More can be learned about similar polygons at brainly.com/question/14285697

#SPJ1

Answer:

there are 458640 different ways to award the six medals.

Step-by-step explanation:

There are two distinct groups in the competition, boys and girls. The order in which the medals are awarded to the groups does not matter, so we can count the number of ways to award medals to the boys and the girls separately, and then multiply the results.

For the boys, there are 7 possible candidates for the gold medal. Once the gold medalist is chosen, there are 6 remaining candidates for the silver medal, and 5 candidates for the bronze medal. So, there are 7 x 6 x 5 = 210 ways to award medals to the boys.

Similarly, for the girls, there are 14 possible candidates for the gold medal. Once the gold medalist is chosen, there are 13 remaining candidates for the silver medal, and 12 candidates for the bronze medal. So, there are 14 x 13 x 12 = 2184 ways to award medals to the girls.

To get the total number of ways to award the six medals, we multiply the number of ways to award medals to the boys by the number of ways to award medals to the girls:

Total number of ways = 210 x 2184 = 458640

Therefore, there are 458640 different ways to award the six medals.

Round each number to the nearest whole

Compare the estimated sum to the actual sum

Look at the tenths place to round to the nearest whole number

The estimated answer is close to the actual answer

Two or more expressions with an Equal sign is called as Equation.

The key phrases used are:

Round each number to the nearest whole

Compare the estimated sum to the actual sum

Look at the tenths place to round to the nearest whole number

The estimated answer is close to the actual answer

These phrases are all related to the process of approximating a sum by rounding the addends to the nearest whole number and comparing the resulting estimate to the exact sum.

Hence, Round each number to the nearest whole

Compare the estimated sum to the actual sum

Look at the tenths place to round to the nearest whole number

The estimated answer is close to the actual answer

To learn more on Equation:

https://brainly.com/question/10413253

#SPJ9