its a angle question.
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Write a function to represent the set of ordered pairs.
{(2, -1), (4, 5), (6, 15), (8, 29)}
Step-by-step explanation:
ES6 has a new Set data structure for storing sets of unique objects. However it is based on object references as opposed to value comparisons. As far as I can tell this makes it impossible to have a set of pairs of numbers without stringifying.
For example, typing in Chrome's console (needs Chrome 38+):
> var s = new Set(); < undefined > s.add([2, 3]); < Set {[2, 3]} > s.has([2, 3]) < false <--- was hoping for 'true'
This appears to be by design: since I passed a different array of [2, 3] to has(), it returns false, because although the contents is the same it only looks at object references, and I allocated a new and different array to pass to has(). I would need to store a reference to the original array I passed to add() to check with has(), but this is not always possible. For example if the number pairs represent co-ordinates, I might need to check if the set has [obj.x, obj.y], but this will always return false since it allocates a new array.
The workaround is to stringify the arrays and key on strings like "2, 3" instead. However in something performance-sensitive like a game engine, it is unfortunate if every set access needs to make a string allocation and convert and concatenate number strings.
Does ES6 provide any feature to solve this problem without stringifying, or is there any feature on the horizon with ES7 that could help as well?
javascriptperformancedata-structuressetecmascript-6
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asked Sep 21 '14 at 13:06

AshleysBrain
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3 Answers
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As you've noted [2, 3] === [2, 3] is false, meaning you can't use Set like this; however, is Set really the best option for you?
You may find that using a two-level data structure like this will be better for you
var o = {}; function add(o, x, y) { if (!o[x]) o[x] = {}; o[x][y] = true; } function has(o, x, y) { return !!(o[x] && o[x][y]); } function del(o, x, y) { if (!o[x]) return; delete o[x][y]; // maybe delete `o[x]` if keys.length === 0
Can you answer plz
у = х + 3
у =-2x-3
Answer:
x = - 2, y = 1
Step-by-step explanation:
Comparing both the equations,
→ y = y → x + 3 = - 2x - 3
=> x + 3 = - 2x - 3
=> x + 2x = - 3 - 3
=> 3x = - 6
=> x = - 6/3 = - 2
Substitute the value of x in any of these:
=> y = x + 3 = - 2 + 3 = 1
Answer:
Step-by-step explanation:
If a solution exists for the system of equations y=y so we can say
x+3=-2x-3 Add 2x to each side
3x+3=-3 Subtract 3 from each side
3x=-6. Divide each side by 3
x=-2, since y=x+3
y=-2+3
y=1
So the solution to the system of equations is the point (x,y)=(-2,1)
How do I know where to put numbers on a graph
Answer:
X axis is on the left of the Coordinates (x,y) and Y axis is on te right
X goes sideways
Y goes Vertical
Step-by-step explanation:
Select the correct answer.
620
530
х
What is the value of x in this triangle?
Answer:
65
Step-by-step explanation:
What is / are the coefficients in this expressions? 3a+7-8n
Answer:
3 and 8
Step-by-step explanation:
3 and 8 are the only numbers that have a variable, or the letter beside it
Graph the system of equations, and determine the
solution.
X + 5y = 10
2x + 10y = 50
Use the graphing tool to graph the system,
Answer:
First one is 2. The second one is 5.
Step-by-step explanation:
i need help w this plss
Answer:
Line a and Line b are parallel. The slopes are equal
Line b is perpendicular to line c. The slopes are different
Step-by-step explanation:
The standard form of an equation is y =- mx+C
m is the slope
Two lines are parallel if they have the same slope and perpendicular if the product of their slope is -1
For Line a: 4x-3y = 2
Rewrite
-3y = -4x+2
y = 4/3 x - 2/3
Slope of line a is 4/3
Line b: y = 4/3x + 2
mx = 4/3x
m = 4/3
slope of line b is 4/3
Line c = 4y+3x = 4
4y = -3x + 4
y = -3/4 x + 1
Slope of line c is -4/3
Since line a and b have the same slope, they arer parallel
mb * mc = 4/3 * -3/4
mb*mc = -1
Since the product of slope of line b and c is -1, they are perpendiclar
The volume of a rectangular prism can be found by multiplying the three side lengths. A bookcase in the shape of a rectangular prism has dimensions (b+8) ft, b ft, and (b+3) ft. Find the volume of the bookcase
Answer:
(b³+11b²+24)ft³
Step-by-step explanation:
Volume of the rectangular prism = Length * Width * Height
Given the dimension
Length = b+8 ft
Width = b ft
Height = (b+3)ft
Volume of the rectangular prism = b(b+8)(b+3)
Volume of the rectangular prism = b(b^2+3b+8b+24)
Volume of the rectangular prism = b(b^2+11b+24)
Volume of the rectangular prism = b(b^2)+b(11b)+1(24)
Volume of the rectangular prism = b^3+11b^2+24
Hence the Volume of the rectangular prism is (b³+11b²+24)ft³
on Monday you buy two apples and three oranges for a total of $14 on Tuesday you buy four apples and five oranges for $24 what does an apple cost and what does an orange cost? what are the two equations
Is (5,2) a solution to this system? x+4y=13 x-y=3 *
Answer:
yes
Step-by-step explanation:
Answer:
Yes.
Step-by-step explanation:
x + 4y = 13
x - y = 3 Subtracting:
0 + 4y - (-y) = 13 - 3
5y = 10
y = 2.
Plug y = 2 into the second equation:
x - 2 = 3
x = 5.
The line l is tangent to the circle with equation x² + y2 = 169 at the point P.
By thinking about the radius or otherwise, determine the gradient of the line l.
Given:
The equation of a circle is
[tex]x^2+y^2=169[/tex]
A tangent line l to the circle touches the circle at point P(12,5).
To find:
The gradient of the line l.
Solution:
Slope formula: If a line passes through two points, then the slope of the line is
[tex]m=\dfrac{y_2-y_1}{x_2-x_1}[/tex]
Endpoints of the radius are O(0,0) and P(12,5). So, the slope of radius is
[tex]m_1=\dfrac{5-0}{12-0}[/tex]
[tex]m_1=\dfrac{5}{12}[/tex]
We know that, the radius of a circle is always perpendicular to the tangent at the point of tangency.
Product of slopes of two perpendicular lines is always -1.
Let the slope of tangent line l is m. Then, the product of slopes of line l and radius is -1.
[tex]m\times m_1=-1[/tex]
[tex]m\times \dfrac{5}{12}=-1[/tex]
[tex]m=-\dfrac{12}{5}[/tex]
Therefore, the gradient or slope of the tangent line l is [tex]-\dfrac{12}{5}[/tex] .
How many inches are in 7 and 1/2 feet?
Answer:
90 inches
Step-by-step explanation: 7 feet*12 inches= 84 and .5 feet*12 inches= 6.
84 inches+ 6inches=90inches
Answer: 1.2ft × 12
= 14.4"
Step-by-step explanation:
GIVE ME DA BRAINS
Kevin just put 20.26 gallons of fuel into his car. There were 3.9 gallons in the car to begin with. How much fuel is in Kevin's car now?
HELPP
Answer:
24.16
Step-by-step explanation:
Help! Will mark brainliest to whoever puts the answer first!
Answer:
1 and 6 (alternate exterior angle)
2 and 5(corresponding angle)
4 and 5(co interior angle)
3 and 5(alternate interior angle)
the ratio of dogs to cats at the local shelter is 2 to 5.there are 20 dogs at the shelter.what is the total number of dogs and cats at the shelter?
20:50 or if you have to add it 70
find the size of the lettered angles
If your test marks in your last 3 tests were: 70%, 82%, and 90%, what's your average test mark?
Answer:
80,66
Step-by-step explanation:
70 + 82 + 90 = 242
for average: you have 3 tests, so 242÷3 = 80,66667
5 of 5
Pip, Angad and Nick share some sweets in
the ratio 3:1:1. Pip gets 36 more sweets
than Nick. How many sweets are there
altogether?
additive inverse of -4/7
Answer:
1/7
Step-by-step explanation:
-3.5(x+9). URGENT : SHOW ALL STEPS PLEASE
Answer:
-3.5x - 31.5
Step-by-step explanation:
-3.5(x+9)
= -3.5x + -3.5(9)
= -3.5x - 31.5
Please due today are 11:59
1/8 + 3/4 in its simplist form
Rewrite 3/4 to have the same denominator as 1/8.
3/4 = 6/8
Now you have 1/8 + 6/8 = 7/8
The answer is 7/8
$6.00 times 200 per day times 65.00 per day for saftey
A student need to fill a tank with 9 liters of water. How many 1/3 liters will it take to fill the tank?
Answer:
Number of [tex]\frac{1}{3}[/tex] liters required to fill the tank = 27
Step-by-step explanation:
Amount of water needed to fill the tank = 9 liters
Measure of water to fill a vessel = [tex]\frac{1}{3}[/tex] liters
Number of [tex]\frac{1}{3}[/tex] liters vessels required to fill the tank = [tex]\frac{9}{\frac{1}{3}}[/tex]
= 9 × [tex]\frac{3}{1}[/tex]
= 27
Therefore, number of [tex]\frac{1}{3}[/tex] liters required to fill the tank = 27
Please help this is 2 step equations even if you answer some I’ll appreciate it. I need the work though. I’ll mark you brainliest !
HELP ILL GIVE BRAINLIEST
In a class of 40 students, 75% of the students
turned in their assignments. How many
students did NOT turn in their assignments?
Answer:
10 students didnt turn in work
Step-by-step explanation:
10. its like saying 100 divided by 25
Help plsssssssssssss
Answer:
CStep-by-step explanation:
use the number then do ÷
if u answer right ill give u brainlyist
Answer:
A
Step-by-step explanation:
'A' because it asks about pros and cons.
The square root of 150 lies between which two consecutive integers?
O 10 and 11
O 11 and 12
O 12 and 13
O 149 and 151
Answer:
12^2 = 144 and 13^2 = 169
So, the answer is 12 and 13
Step-by-step explanation: