Answer:
A relational database stores data in a series of tables so that the data models a mathematical theory of relations. The model allows for queries based on projection, selection, and join, among other operations, and connects the data in the tables by way of keys.
Answer:
Well, I guess in a formal sense you could call relational algebra a type of logic, which puts it into the realm of ‘math’, though I don’t think most mathematicians would look at it as being a very significant area, more ‘applied logic’ than anything else.
That being said, relational algebra DOES present some formalisms in the shape of relations, tuples, normalizations, and denormalization, etc. There is also a model of sequential operations and thus the underpinnings of the ACID database concept.
Since the overwhelming primary use of RA has been as a way to structure our ideas about SQL RDBMSes there isn’t really a lot of deep theory there. I don’t think anyone has really built any other models of RA beyond an RDBMS. There have been limited non-SQL RDBMS implementations, but AFAIK none of them are really actively maintained today.
Which of the following expressions represents the distance between -3.9 and -4.7
Answer:
None of the above
Step-by-step explanation:
Distance is the difference between two positions. That is x1- x2 Since both numbers were negative, you would want the absolute value of one plus the other, because subtracting a negative results in a positive. For this example the distance would look more like this:
| -4.7 - ( -3.9 ) | = .8
7. Define a variable and write an expression for the phrase.
8 minus a number
find missing side of triangle, help!
Answer:
2√10 km
Step-by-step explanation:
By Pythagoras theorem,
x^2 + 9^2 = 11^2
x^2 + 81 = 121
x^2 = 121 - 81
x^2 = 40
= 4 x 10
x^2 = 2^2 x 10
x = 2√10 km
what is the answer to this?
Answer:
29
Step-by-step explanation:
43.25-7=36.25
36.25/1.25=29
A boy who is 1.4m tall, sighted the top of a flag pole at an angle of elevation of 36°. if the boy is 9.5m away from the flag pole, calculate the height of the flag pole
Answer:
The height of flag pole=8.3m
Step-by-step explanation:
We are given that
Height of boy=1.4 m
[tex]\theta=36^{\circ}[/tex]
Distance of boy from the flag pole=9.5 m
We have to find the height of the flag pole.
BCDE is a rectangle
BC=ED=1.4 m
CD=BE=9.5 m
In triangle ABE
[tex]\frac{AB}{BE}=tan36^{\circ}[/tex]
Using the formula
[tex]tan\theta=\frac{Perpendicular\;side}{base}[/tex]
[tex]\frac{AB}{9.5}=tan 36^{\circ}[/tex]
[tex]AB=9.5tan36^{\circ}[/tex]
AB=6.90 m
Height of flag pole=AB+BC=6.90+1.4
Height of flag pole=8.3m
(r-3)(r-1)
Help me please!!!
Answer:
= r²−4r+3
Step-by-step explanation:
(r - 3) (r - 1)
(r x r) + (r x -1) + (-3 x r) + (-3 x -1)
r² + - r - 3r + 3
= r²−4r+3
At a party there are 30 students over the age of 21 and 15 under the age of 21. You select a representative sample of 5to interview about attitude towards alcohol. Explain your method and select ypur sample
Answer:
Stratified sampling
Step-by-step explanation:
Given
[tex]30 \to 21\ and\ above[/tex]
[tex]15 \to Under\ 21[/tex]
Required
The type of sampling method
From the question, we understand that, the sample are divided into two categories. This means that each person in each person do not have the same probability of being selected.
Such method is a stratified sampling
What is 2/3 divided by 1/6
Answer:
4
Step-by-step explanation:
Answer:
4
Step-by-step explanation:
When we divide fractions, we are essentially multiplying by the reciprocal of the fraction.
2/3 ÷ 1/6
= 2/3 × 6
= 12/3
= 4
A larger number is double the sum of 3 and a smaller number. The larger number is 2 less than 3 times the smaller
number. If y represents the larger number and x represents the smaller number, which equations model the situation?
Check all that apply.
Oy - 3x-2
3x-y = 2
3x-y=-2
y=2-3x
Oy=2(x+3)
Answer:
not sure what the O is there for?
if it is zero then Oy would make Oy=2(x+3) not correct
3x-y = 2
y=2(x+3)
Step-by-step explanation:
)
Find f(-3) if f(x) = x^2
6
-9
9
-6
Answer:
B. -9
Step-by-step explanation:
The equation would be f(-3)=-3^2
3*3 is 9
Add the - back on, and you get -9
I hope this helps!
Plz help me I don’t understand
Answer:
Step-by-step explanation:
Take two points on the line and find the slope.
(1 , 2) ; (4 , 4)
Slope = [tex]\frac{y_{2}-y_{1}}{x_{2}-x_{1}}\\\\[/tex]
[tex]=\frac{4-2}{4-1}\\\\=\frac{2}{3}[/tex]
m = 2/3 & (1 , 2)
Slope point form : y - y1 = m(x-x1)
[tex]y - 2 = \frac{2}{3}*(x - 1)\\\\y - 2 =\frac{2}{3}x - \frac{2}{3}\\\\y =\frac{2}{3}x-\frac{2}{3}+2\\\\y = \frac{2}{3}x-\frac{2}{3}+\frac{2*3}{1*3}\\\\y=\frac{2}{3}x-\frac{2}{3}+\frac{6}{3}\\\\y=\frac{2}{3}x+\frac{4}{3}\\\\Multiply \ equation \ by \ 3\\\\3y = 2x + 4\\\\2x - 3y + 4 = 0[/tex]
What expression represents the product of b and 34
Answer:
b + 24
Step-by-step explanation:
b and 24 would be b + 24
Use the zero product property to find the solutions to the equation x2 + 12 = 7x.
x = –4 or x = 3
x = –4 or x = –3
x = –3 or x = 4
x = 3 or x = 4
Answer:
In a product like:
a*b = 0
says that one of the two terms (or both) must be zero.
Here we have our equation:
x^2 + 12 = 7x
x^2 + 12 - 7x = 0
Let's try to find an equation like:
(x - a)*(x - b) such that:
(x - a)*(x - b) = x^2 + 12 - 7x
we get:
x^2 - a*x - b*x -a*-b = x^2 - 7x + 12
subtracting x^2 in both sides we get:
-(a + b)*x + a*b = -7x + 12
from this, we must have:
-(a + b) = -7
a*b = 12
from the first one, we can see that both a and b must be positive.
Then we only care for the option with positive values, which is x =3 or x = 4
replacing these in both equations, we get:
-(3 + 4) = -7
3*4 = 12
Both of these equations are true, then we can write our quadratic equation as:
(x - 3)*(x - 4) = x^2 + 12 - 7x
The correct option is the last one.
Answer:
d
Step-by-step explanation:
solve the equation
45 = 3(x + 1)
Answer:
x = 14
Step-by-step explanation:
45 = 3(x + 1)
Distribute the 3
3(x) = 3x
3(1) = 3
We now have 45 = 3x + 3
Subtract 3 from both sides
45 - 3 = 42
3 - 3 cancels out
We now have 42 = 3x
Divide both sides by 3
42/3 = 14
3x / 3 = x
We're left with x = 14
Answer:
x = 14
Step-by-step explanation:
45 = 3(x + 1)
Distribute
45 = 3x + 3
-3 -3
----------------
42 = 3x
---- ----
3 3
14 = x
Graph 3 points on the line y = x+6
Y=x+6
X+y=8
Answer:
We can first, determine two points on the line:
For:
x
=
0
y
=
0
−
6
y
=
−
6
or
(
0
,
−
6
)
For:
x
=
6
y
=
6
−
6
y
=
0
or
(
6
,
0
)
Next, we can plot these two points on the grid:
graph{(x^2+(y+6)^2-0.125)((x-6)^2+y^2-0.125)=0 [-20, 20, -10, 10]}
Now, we can draw a line through the two points to graph the line for the equation:
graph{(x^2+(y+6)^2-0.125)((x-6)^2+y^2-0.125)(y-x+6)=0 [-20, 20, -10, 10]}
For every 19 litres of petrol a car can run for 50 km . How much petrol do you need ( to 1 DP ) to ensure the car has enough petrol of a trip that is 130 km
Answer:
49.4 liters
Step-by-step explanation:
we have the basic ratio between liters of petrol (gasoline) and distance driven :
19/50
now, the same ratio has to apply, when we talk about 130 km instead of just 50.
so,
19/50 = x/130
x = 130×19/50 = 13×19/5 = 49.4 liters
if I may add, this is a very bad or at least very, very big car based on today's standards ...
hello there i have no clue how to graph this function, f (x) =3/2 (2) ^x
pls answer with explanation!
The manager of a small baseball stadium uses the equation y = 9000 -2.4x to model the relationship between y, the number of unfilled seats in the
stadium, and x, the number of cars in the parking lot. According to the model, how many cars will be in the parking lot when there are no unfilled seats in the stadium?
Answer:
3,750 cars.
Step-by-step explanation:
We are given that the equation:
[tex]y=9000-2.4x[/tex]
Models the relationsip between y, the number of unfilled seats in the stadium, and x, the number of cars in the parking lot.
We want to determine the number of cars in the parking lot when there are no unfilled seats in the stadium.
When there are no unfilled seats in the stadium, y = 0. Thus:
[tex]0=9000-2.4x[/tex]
Solve for x. Subtract 9000 from both sides:
[tex]-2.4x=-9000[/tex]
Divide both sides by -2.4:
[tex]x=3750[/tex]
So, there will be 3,750 cars in the parking lot when there are no unfilled seats in the stadium.
PLZ HELP
Which statement is an example of the reflexive property of congruence?
Help and explain !!!!( Solve using the substitute method )
Answer:
x=13
y= -9
(13, -9)
Step-by-step explanation:
If we are solving using the substitution method, we can take the first equation and set it to y so y=4-x.
Then, we can take that equation and plug it into the bottom one so
3x+4(4-x)=3
Simplify:
3x+16-4x=3
-x=-13
x=13
We can then plug 13 into any of the two given equations (I am just going to plug it into the top one)
So, 13+y=4 which y= -9
Let be the set of permutations of whose first term is a prime. If we choose a permutation at random from , what is the probability that the third term is equal to
Answer:
[tex]Pr = \frac{1}{6}[/tex]
Step-by-step explanation:
Given
[tex]S = \{1,2,3,4,5\}[/tex]
[tex]n = 5[/tex]
Required
Probability the third term is 3
First, we calculate the possible set.
The first must be prime (i.e. 2, 3 and 5) --- 3 numbers
[tex]2nd \to 4\ numbers[/tex]
[tex]3rd \to 3\ numbers[/tex]
[tex]4th \to 2\ numbers[/tex]
[tex]5th \to 1\ number[/tex]
So, the number of set is:
[tex]S = 3 * 4 * 3 * 2 * 1[/tex]
[tex]S = 72[/tex]
Next, the number of sets if the third term must be 2
[tex]1st \to 2[/tex] i.e. 1 or 5
[tex]2nd \to 3\ numbers[/tex] ---- i.e. remove the already selected first term and the 3rd the compulsory third term
[tex]3rd \to 1\ number[/tex] i.e. the digit 2
[tex]4th \to 2\ numbers[/tex]
[tex]5th \to 1\ number[/tex]
So
[tex]r = 2 * 3 * 1 * 2 * 1[/tex]
[tex]r = 12[/tex]
So, the probability is:
[tex]Pr = \frac{r}{S}[/tex]
[tex]Pr = \frac{12}{72}[/tex]
[tex]Pr = \frac{1}{6}[/tex]
luis tiene 3 años más que
Ines. La edad de Antonio
suma de las edades de ambos.
¿ Cuales Son las edades de Luis
e Ine's si antonio tiene 15 años?
Answer:
NMHGJMHBNKJ6T76 5745
Step-by-step explanation:
7657457657776767
Let the universal set U = {weekdays}. If T = {Tuesday, Thursday}, what is T'?
Answer:Monday, Wednesday and Friday.
Step-by-step explanation:
It’s the other weekdays.
ratio of 55 paise is to 1 rupees
Answer:
You have to equal the unit first,
as 1 Rupee = 100 paise,
so,
55paise: 100paise,
= 11:20
I hope it hepled : )
At 2:48, what is the degree measure of the smaller angle formed by the hour and minute hands of a 12 hour clock?
Answer:
The smaller angle will be "156°".
Step-by-step explanation:
According to the question,
Before 12, the minute hand at 48 minutes:
= [tex]60-48[/tex]
= [tex]12[/tex] (minutes to 12)
So,
= [tex]12 \ minutes+14 \ minutes[/tex]
= [tex]26 \ minutes[/tex]
hence,
The smaller angle will be:
= [tex]26\times 6^{\circ} \ each[/tex]
= [tex]156^{\circ}[/tex]
Answer:
The angle is 204 degree.
Step-by-step explanation:
The angle turned by minute hand in 1 minute is 6 degree
The angle turned by the hour hand in 1 hour is
For the hour hand :
The angle turned in 1 hour = 360/12 = 30degree
At 2 : 00 , the angle covered = 30 x 2 = 60 degree
In each minute the hour hand moves = 30 degrees / hour x 1 hour/60 min
= 1/2 degree
So at 2: 48 the hour hand is at 2*30 + 48 * 1/2 = 84 degrees
For the minute hand:
In each minute it turns = 6 degrees
So, at 48 minutes the minute hand is at 48 x 6 = 288 degrees
So, the angle between them is 288 - 84 = 204 degrees
Solve for x. Round to the nearest tenth of a degree, if necessary.
Answer:
x ≈ 39.3°
Step-by-step explanation:
Using the cosine ratio in the right triangle
cos x = [tex]\frac{adjacent}{hypotenuse}[/tex] = [tex]\frac{KL}{KM}[/tex] = [tex]\frac{6.5}{8.4}[/tex] , then
x = [tex]cos^{-1}[/tex] ([tex]\frac{6.5}{8.4}[/tex] ) ≈ 39.3° ( to the nearest tenth )
Step-by-step explanation:
Cos theta =Base/hypotenuse
Base=KL= 6.5
Hypotenuse=KM=8.4
Cos X=
[tex] \frac{6.5}{8.4} \\ [/tex]
X=
[tex] {cos}^{ - 1} \frac{6.5}{8.4} [/tex]
X=39.30 (2decimal)
Brainliest please~
SOMEONE PLEASE HELP ME OUT!!!!
Answer:
40/30
Step-by-step explanation:
Since tan∅= o/a, 40 is opposite, and 30 is adjacent to angle A, 40/30 is the ratio for tanA.
Answer:40/30
Step-by-step explanation:
....
How would the expression x2 -9 be rewritten using Difference of Squares?
Answer:
(x + 3) (x - 3)
Step-by-step explanation:
[tex]a^{2} -b^2=(a+b)(a-b)[/tex] where a = x and b = 3
x^2 - 3^2 =
x^2 - 9 =
(x + 3)
(x - 3)
Answer:
Step-by-step explanation:
x²-9=x²-3²
Find the area of the parallelogram
Simplify the expression. (6)8 + (6)3
Answer:
66
Step-by-step explanation:
Use the PEMDAS order. Multiplication comes before addition so it simplifies to 6(8)+(6)3
=48+18
=66