Answer:
See below for proof.
[tex]S_{500}=125250[/tex]
Step-by-step explanation:
Given arithmetic series:
1 + 2 + 3 + … + nTherefore:
[tex]S_n=1+2+3+...+(n-2)+(n-1)+n[/tex]
[tex]S_n=1+(1+1)+(1+2)+...+(1+n-3)+(1+n-2)+(1+n-1)[/tex]
[tex]S_n=1+(1+1)+(1+2(1))+...+(1+(n-3)(1))+(1+(n-2)(1))+(1+(n-1)(1))[/tex]
Let:
a = first term = 1d = common difference = 1n = nth termTherefore:
[tex]S_n=a+(a+d)+(a+2d)+...+(a+(n-3)d)+(a+(n-2)d)+(a+(n-1)d)[/tex]
Reverse the order:
[tex]S_n=(a+(n-1)d)+(a+(n-2)d)+(a+(n-3)d)+...+(a+2d)+(a+d)+a[/tex]
Add the two expressions for Sₙ:
[tex]2S_n=(2a+(n-1)d)+(2a+(n-1)d)+(2a+(n-1)d)+...+(2a+(n-1)d)[/tex]
Therefore, the term (2a + (n – 1)d) has been repeated n times:
[tex]2S_n=n(2a+(n-1)d)[/tex]
Divide both sides by 2:
[tex]S_n=\dfrac{1}{2}n(2a+(n-1)d)[/tex]
[tex]S_n=\dfrac{1}{2}n(a+a+(n-1)d)[/tex]
Replace a with a₁ (first term) and a + (n – 1)d with aₙ (last term):
[tex]S_n=\dfrac{1}{2}n(a_1+a_n)[/tex]
To find the sum of the series 1 + 2 + 3 + ... + 500, substitute the following values into the formula:
a₁ = 1aₙ = 500n = 500Therefore:
[tex]\implies S_{500}=\dfrac{1}{2}(500)(1+500)[/tex]
[tex]\implies S_{500}=250(501)[/tex]
[tex]\implies S_{500}=125250[/tex]
1.7. In a Maths class, the girl to boy ratio is 7:5.
If there are 20 boys, how many girls are in the class?
Answer:
28 girls
Step-by-step explanation:
Let total students be ‘X’
No of girls = (X-20)
Girls/Boys=7/5=(X-20)/20
7(20) =5(X-20)
140=5X-100
5X=240
X = 240/5
X =48
So, Total Students are 48
No of girls = (X-20) = 48-20 = 28
Determine the opposite of 3p^7-8p
Step-by-step explanation:
Maybe you should flip flop
finding area of circle with radius , giving brainliest :)) pls help asap
Answer:
number 2 is the answer or 4*pi inches² or 12.6
Step-by-step explanation:
Please need help you know this
Answer:
Rule: Output = 2 * input + 1
Right blank: Output = - 1
Left blank: Input = 4
Step-by-step explanation:
Rule
Start with the rule
Output = 2 * input + 1
Let the output = y
Let the input = x
y = 2x + 1
Now
Right Blank
x = - 1
y = 2*-1 + 1
y = -2 + 1
y = - 1
That's the output for -2
Left Blank
The second blank asks you to solve for the input (x) The output (y) is 9
9 = 2x + 1 Subtract 1 from both sides
9-1 = 2x Combine
8 = 2x Divide by 2
8/2 = 2x/2
x = 4
PLEASE HELP MEEEEE PLEASE!
Answer: my best guess would be c
Step-by-step explanation: I hope you figure this out maybe use Socratic app that might help
Answer:
(-2,2)
Step-by-step explanation:
the red line is y = x + 4 ( we know this as x = -4 is the x intercept)
the green one is y = -x (it intercepts in origin)
so, we equal the two equations to each other to get the interception point:
x + 4 = - x
4 = -2x
x = -2
we substitute x = -2 in any of the equations we get
y = -2 + 4 = 2 or y = -(-2) = 2
so the point is (-2,2) which is option C.
Yo pls help me out, the question is on the picture.
ill mark brainliest if its correct. NO LINKS!
Bentley had $25 to spend on 5 paintbrushes for his art class. After buying them, Bentley had $5 left. How much did each of the paintbrushes cost?
Answer:
$4
Step-by-step explanation:
$25-$5=20
20 divided by 5 = 4
how do i solve this question
Answer:
18.18
Step-by-step explanation:
total sum of angle of quadrilateral is 360
70+60+ 7x-4+4x-3=360
160-7 +11x =360
153 +11x =360
11x=360-153
x=207/11
x=18.18
Plz help me with this one!
Step-by-step explanation:
[tex]y = x + 5 \: \: \: \: y = - 3x + 1 \\ y = x + 5 \: \: \: \: x + 5 = - 3x + 1 \\ y = x + 5 \: \: \: \: 4x = - 4 \\ y = x + 5 \: \: \: \: x = - 1 \\ y = 4 \: \: \: \: x = - 1[/tex]
The low temperature at 6:45 A.M. was −22°F. At 3:15 P.M. the temperature was 5°F. What was the range of temperature for the day? A −27°F B −17°F C 17°F D 27°F
Answer:
D
Step-by-step explanation:
-22°F+27°F=5°F
have a nice day or evening
Answer:
D
Step-by-step explanation:
I took the test
HELP ME IN NUMBER 1 AND 2
Answer:
Number is is A Number 2 is 77 trust ik math
PLEASE HELP I HAVE NO IDEA WHAT TO DO!!!
Answer: multiply and round I'm pretty sure tell me if u want me to multiply for u
Step-by-step explanation:
How do you work the problem 6y < 18 out
Answer:
y<3
Step-by-step explanation:
6y<18
y<18/6
y<3
I hope this helps
Answer: you can see what number times 6 gets you 18 so it would be y<3
Step-by-step explanation:
add 4x²y,-2xy²,-5xy²,3x²y plz explain
A playground is rectangular with a length of 12 miles. If the area of the playground is 58 square miles, what is its width? Input your answer as a fraction.
Answer:
4 5/6 miles
Step-by-step explanation:
Area of a rectangle = length x width
58 = 12 x width
to find width, divide both sides of the equation by 12
58/12 = 4 whole number and 10 would remain
4 10/12
to simply, divide numerator and denominator by 2
4 5/6 miles
6 grade math pls help
answer
measure of o is 75
and n is same as o as the sides are same
hope this helps you
The median for the 5 numbers 2647, 1956, 2250, 2141, and x is 2141. What is the largest possible value for the number x?
Answer:
2140
Step-by-step explanation:
Median can be described as the number that lies in the middle of a set of arranged observations. the observations can be arranged in ascending or descending order
in a set of 5 numbers, the median would be the 3rd number
the median is 2141. there was to be 2 numbers before and after 2141
1956, x 2141, 2250, 2647
the largest possible value of x is 2140. this is the largest number that is less than 2140
HELP MEEEEEEEEEEEE 3.0
Answer:
I think that J would be the answer , It is more reliable than the left ones .
Hope it was helpful , good luck ^^
If each square in the following floor plan represents 2.5 feet, what are the dimensions of the living room?
Margaret owns (5/6) of a section of land. She planted corn on (1/4) of her land. What fraction of the entire section is planted with Margaret’s corn?
Answer:
3/5
Step-by-step explanation:
subtract the fractions then turn the decimal into a fraction.
A number "X" greater than 8
Answer:
X > 8
Step-by-step explanation:
Using the keywords greater than helps you.
On a number line, show all values of x for which |x|>3
1. Mr. Jay has 24 students and 75% of them are boys. How many are boys?
Answer:
18
Heart if this helped
Freddy exercise 3.5 hours per day 4 days last week he burned 440 calories per hour while exercising how many calories did Freddie burn by exercising last week
Answer:
6,160 calories
Step-by-step explanation:
total hours of exercising = 3.5 x 4 = 14
burns 440 calories per each hour
total calories burned is 440 x 14
how much markup is $75 to $180
Answer:
105
Step-by-step explanation:
75+105 =180
John ran a race in 36 minutes. If each lap takes 9 minutes to run, write and solve an equation to find out how many laps John had to run.
SHOW YOUR WORK AND SOLVE PLEASE
Answer:
4 laps
Step-by-step explanation:
Solved using a proportion.
[tex]\frac{1}{9} = \frac{y}{36}[/tex]
9 × y = 1 × 36
9y = 36
9y ÷ 9 = 36 ÷ 9
y = 4
HELP! I NEED THIS QUESTION ANSWERED ASAP!!!!!
HERE!
Angle X measures 53°
What type of angle is angle X?
Answers:
1 ) Obtuse
2) Right
3) Acute
Answer:
3 ) Acute
Step-by-step explanation:
Acute Angle - An angle less than 90 degrees.
Right Angle - An angle that is exactly 90 degrees.
Obtuse Angle - An angle more than 90 degrees and less than 180 degrees.
Straight Angle - An angle that is exactly 180 degrees.
Answer:
3)Acute
Step-by-step explanation:
any angle that is under a 90 degree angle or a right angle, is an acute angle. any angle that is above 90 degrees or a right angle is an obtuse andgle
Can someone please help me
I NEED HELP!
The function f(x) is a quadratic function and the zeros of f(x) are - 2 and 5. The y-intercept of f(x) is 30. Write the equation of the quadratic polynomial in standard form.
f(x)=___________
Answer:
Step-by-step explanation:
First of all you have to put the zeros into factor form.
y1 = (x + 2)(x - 5)
Notice that the x changes sigh. You say that the zeros are -2 and 5. To get y1 to go to zero, you must make x the opposite sign of what you are given.
Now you have to expand the factored form to get the standard form
y = x^2 + 2x - 5x - 10
y = x^2 - 3x - 10
That's not the right answer.
f(0) = 30 but you have - 10 at the end so you have to multiply the factored form by - 3
-3(f(x)) = -3(x + 2)(x - 5)
-3(f(x)) = -3(x^2 - 3x - 10)
f(x) = -3x^2 + 9x + 30
f(0) = -3(0)^2 + 9(0) + 30
f(0) = 30
The quadratic still has roots of (x +2)(x - 5) but that 3 makes the y intercept = 30.
See the graph below.
I need help fast please
Answer:
-2/3
Step-by-step explanation:
8^(x+2) =8^-2x
since the base are the same we deal with the exponent
x+2=-2x
x= -2/3