[tex]\displaystyle\bf\\Explanations:\\\\The~similarity~ratio~of~two~similar~cones=k\\\\k=is~the~ratio~between~2~corresponding~lengths\\\\k=\frac{R_1}{R_2}=\frac{h_1}{h_2}\\\\The~ratio~between~2~corresponding~areas~of~similar~cones=k^2\\\\\frac{Area~1}{Area~2}=k^2\\\\The~ratio~between~the~volumes~of~the~2~similar~cones=k^3\\\\\frac{Volume~1}{Volume~2}=k^3[/tex]
.
[tex]\displaystyle\bf\\Solving:\\\\Volume1=108~m^3\\\\Volume2=4m^3\\\\k^3=\frac{108}{4}\\\\k^3=27~~\Big|\sqrt{~}\\\\k=\sqrt[\b3]{27}\\\\k=3\\\\Area1=54~m^2\\\\\frac{Area~1}{Area~2}=k^2\\\\\frac{54}{Area~2}=3^2\\\\\frac{54}{Area~2}=9\\\\Area2=\frac{54}{9}\\\\\boxed{\bf Area2=6 m^2}[/tex]
The portion of the parabola y²=4ax above the x-axis, where is form 0 to h is revolved about the x-axis. Show that the surface area generated is
A=8/3π√a[(h+a)³/²-a³/2]
Use the result to find the value of h if the parabola y²=36x when revolved about the x-axis is to have surface area 1000.
Answer:
See below for Part A.
Part B)
[tex]\displaystyle h=\Big(\frac{125}{\pi}+27\Big)^\frac{2}{3}-9\approx7.4614[/tex]
Step-by-step explanation:
Part A)
The parabola given by the equation:
[tex]y^2=4ax[/tex]
From 0 to h is revolved about the x-axis.
We can take the principal square root of both sides to acquire our function:
[tex]y=f(x)=\sqrt{4ax}[/tex]
Please refer to the attachment below for the sketch.
The area of a surface of revolution is given by:
[tex]\displaystyle S=2\pi\int_{a}^{b}r(x)\sqrt{1+\big[f^\prime(x)]^2} \,dx[/tex]
Where r(x) is the distance between f and the axis of revolution.
From the sketch, we can see that the distance between f and the AoR is simply our equation y. Hence:
[tex]r(x)=y(x)=\sqrt{4ax}[/tex]
Now, we will need to find f’(x). We know that:
[tex]f(x)=\sqrt{4ax}[/tex]
Then by the chain rule, f’(x) is:
[tex]\displaystyle f^\prime(x)=\frac{1}{2\sqrt{4ax}}\cdot4a=\frac{2a}{\sqrt{4ax}}[/tex]
For our limits of integration, we are going from 0 to h.
Hence, our integral becomes:
[tex]\displaystyle S=2\pi\int_{0}^{h}(\sqrt{4ax})\sqrt{1+\Big(\frac{2a}{\sqrt{4ax}}\Big)^2}\, dx[/tex]
Simplify:
[tex]\displaystyle S=2\pi\int_{0}^{h}\sqrt{4ax}\Big(\sqrt{1+\frac{4a^2}{4ax}}\Big)\,dx[/tex]
Combine roots;
[tex]\displaystyle S=2\pi\int_{0}^{h}\sqrt{4ax\Big(1+\frac{4a^2}{4ax}\Big)}\,dx[/tex]
Simplify:
[tex]\displaystyle S=2\pi\int_{0}^{h}\sqrt{4ax+4a^2}\, dx[/tex]
Integrate. We can consider using u-substitution. We will let:
[tex]u=4ax+4a^2\text{ then } du=4a\, dx[/tex]
We also need to change our limits of integration. So:
[tex]u=4a(0)+4a^2=4a^2\text{ and } \\ u=4a(h)+4a^2=4ah+4a^2[/tex]
Hence, our new integral is:
[tex]\displaystyle S=2\pi\int_{4a^2}^{4ah+4a^2}\sqrt{u}\, \Big(\frac{1}{4a}\Big)du[/tex]
Simplify and integrate:
[tex]\displaystyle S=\frac{\pi}{2a}\Big[\,\frac{2}{3}u^{\frac{3}{2}}\Big|^{4ah+4a^2}_{4a^2}\Big][/tex]
Simplify:
[tex]\displaystyle S=\frac{\pi}{3a}\Big[\, u^\frac{3}{2}\Big|^{4ah+4a^2}_{4a^2}\Big][/tex]
FTC:
[tex]\displaystyle S=\frac{\pi}{3a}\Big[(4ah+4a^2)^\frac{3}{2}-(4a^2)^\frac{3}{2}\Big][/tex]
Simplify each term. For the first term, we have:
[tex]\displaystyle (4ah+4a^2)^\frac{3}{2}[/tex]
We can factor out the 4a:
[tex]\displaystyle =(4a)^\frac{3}{2}(h+a)^\frac{3}{2}[/tex]
Simplify:
[tex]\displaystyle =8a^\frac{3}{2}(h+a)^\frac{3}{2}[/tex]
For the second term, we have:
[tex]\displaystyle (4a^2)^\frac{3}{2}[/tex]
Simplify:
[tex]\displaystyle =(2a)^3[/tex]
Hence:
[tex]\displaystyle =8a^3[/tex]
Thus, our equation becomes:
[tex]\displaystyle S=\frac{\pi}{3a}\Big[8a^\frac{3}{2}(h+a)^\frac{3}{2}-8a^3\Big][/tex]
We can factor out an 8a^(3/2). Hence:
[tex]\displaystyle S=\frac{\pi}{3a}(8a^\frac{3}{2})\Big[(h+a)^\frac{3}{2}-a^\frac{3}{2}\Big][/tex]
Simplify:
[tex]\displaystyle S=\frac{8\pi}{3}\sqrt{a}\Big[(h+a)^\frac{3}{2}-a^\frac{3}{2}\Big][/tex]
Hence, we have verified the surface area generated by the function.
Part B)
We have:
[tex]y^2=36x[/tex]
We can rewrite this as:
[tex]y^2=4(9)x[/tex]
Hence, a=9.
The surface area is 1000. So, S=1000.
Therefore, with our equation:
[tex]\displaystyle S=\frac{8\pi}{3}\sqrt{a}\Big[(h+a)^\frac{3}{2}-a^\frac{3}{2}\Big][/tex]
We can write:
[tex]\displaystyle 1000=\frac{8\pi}{3}\sqrt{9}\Big[(h+9)^\frac{3}{2}-9^\frac{3}{2}\Big][/tex]
Solve for h. Simplify:
[tex]\displaystyle 1000=8\pi\Big[(h+9)^\frac{3}{2}-27\Big][/tex]
Divide both sides by 8π:
[tex]\displaystyle \frac{125}{\pi}=(h+9)^\frac{3}{2}-27[/tex]
Isolate term:
[tex]\displaystyle \frac{125}{\pi}+27=(h+9)^\frac{3}{2}[/tex]
Raise both sides to 2/3:
[tex]\displaystyle \Big(\frac{125}{\pi}+27\Big)^\frac{2}{3}=h+9[/tex]
Hence, the value of h is:
[tex]\displaystyle h=\Big(\frac{125}{\pi}+27\Big)^\frac{2}{3}-9\approx7.4614[/tex]
You seem to have left out that 0 ≤ x ≤ h.
From y² = 4ax, we get that the top half of the parabola (the part that lies in the first quadrant above the x-axis) is given by y = √(4ax) = 2√(ax). Then the area of the surface obtained by revolving this curve between x = 0 and x = h about the x-axis is
[tex]2\pi\displaystyle\int_0^h y(x) \sqrt{1+\left(\frac{\mathrm dy(x)}{\mathrm dx}\right)^2}\,\mathrm dx[/tex]
We have
y(x) = 2√(ax) → y'(x) = 2 • a/(2√(ax)) = √(a/x)
so the integral is
[tex]4\sqrt a\pi\displaystyle\int_0^h \sqrt x \sqrt{1+\frac ax}\,\mathrm dx[/tex]
[tex]=\displaystyle4\sqrt a\pi\int_0^h (x+a)^{\frac12}\,\mathrm dx[/tex]
[tex]=4\sqrt a\pi\left[\dfrac23(x+a)^{\frac32}\right]_0^h[/tex]
[tex]=\dfrac{8\pi\sqrt a}3\left((h+a)^{\frac32}-a^{\frac32}\right)[/tex]
Now, if y² = 36x, then a = 9. So if the area is 1000, solve for h :
[tex]1000=8\pi\left((h+9)^{\frac32}-27\right)[/tex]
[tex]\dfrac{125}\pi=(h+9)^{\frac32}-27[/tex]
[tex]\dfrac{125+27\pi}\pi=(h+9)^{\frac32}[/tex]
[tex]\left(\dfrac{125+27\pi}\pi\right)^{\frac23}=h+9[/tex]
[tex]\boxed{h=\left(\dfrac{125+27\pi}\pi\right)^{\frac23}-9}[/tex]
Investors buy a studio apartment for $140,000. Of this amount, they have a down payment of
$42,000. Their down payment is what percent of the purchase price? What percent of the purchase
price would a $49,000 down payment be?
Their down payment is % of the purchase price.
Answer:
their down payment is 30%
Step-by-step explanation:
Answer:
Step-by-step explanation:
if the price of the apartment is 140,000 dollars
lets find out how much is 1%
140,000/100=1400
42,000/1400=30
42,000 is 30% of the apt price
49,000/1400=35
49,000 is 35% of the apt price
A 4 inch by 6 inch picture is placed in a gram that creates a uniform border of x inches around the picture
Answer:
1.5 inches.
Step-by-step explanation:
A picture measuring 4 inches by 6 inches is placed inside a frame which has equal width around the entire picture.
The area of the frame and the picture is 63 square inches.
When you graph a system of equations what are the three possible outcomes?
Answer:
i think its a beaner
Step-by-step explanation:
Which represents the equation of the roll line?
Answer:
A) y=3x-4
Step-by-step explanation:
what is 7/9 of 1 1/14
Answer:
1.5555556
1 5/9
14/9
Step-by-step explanation:
Find the value of 7C7
Step-by-step explanation:
If there were 7 items, the number of ways to choose 7 out of the 7 items is only 1 way, which is to get all of them.
=> 7C7 = 1.
2x^2-20x+100 quadratic formula
Answer:10
Step-by-step explanation:
PLSSSSSS I NEED HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Simplify the Expression:
[tex]\sqrt{9a^{2} }[/tex], if a<0
[tex]\sqrt{9a^{2}}=\sqrt{9}\sqrt{a^{2}}=3|a|[/tex]
As [tex]a < 0[/tex], [tex]|a|=-a[/tex], so [tex]3|a|=\boxed{-3a}[/tex]
HELP ASAP PLEASE LEAVE SMALL EXPLANATION ITS DUE RLLY SOON
Answer:
1. y=3x-4
2. y=-3x+4
3. y= -1/3x+4
4. y= 1/3x-4
Step-by-step explanation:
1. slope= change in y/ change in x
slope= -1-(-4)/1-0=3
y=3x+b
-4=3(0)+b
b=-4
y=3x-4
2. slope=4-10/0-(-2)= -3
y=-3x+b
b=4
y=-3x+4
3. slope= -1/3
y=-1/3x+b
3= -1/3(3)+b
3= -1+b
b=4
y= -1/3x+4
4. y= 1/3x-4 (last one)
HELP PLS DUE IN 10 MIN PLS
Samuel orders four DVDs from an online music store. Each DVD costs $9.91. He has a 25% discount code,
and sales tax is 6.75%. Round sales tax amounts to the nearest cent. What is the total cost of his order?
The total cost of Samuel's order is sl
Answer:
The total cost is $32.40
Step-by-step explanation:
9.91 x 4 = 39.64
25% of 39.64 is 9.91
39.64 - 9.91 = 29.73
6.75% of 39.64 is 2.67
29.73 + 2.67 = 32.40
Please help me with both the questions ty.
Answer:
4) 26+4/842-/×375-^×
5)/^9+37+×+454+12
Step-by-step explanation:
f(x) = x2. What is g(x)?
Mrs. Matthews wrote three math expressions on the board.
She asked her students which expression would result in a product greater than 7.
Enter the number of the expression that Mrs. Matthews's students should have chosen.
Expression
will result in a product greater than 7.
Answer:
expression 3
because expression 1 = 1
and expression 2 = 7
URGENT 25 POINTS MATH EQUATION PLEASE NO POINT STEAL!
Answer:
it is diff because o the parentheses
Step-by-step explanation:
You run 6 miles in one hour and 24 miles in four hours.
a. 6 miles
per hour
c. 4 hours
b. 4 miles per hour
d. 6 miles
Answer:b
Step-by-step explanation:
answer this!! will mark brainliest! 20 points
Answer:
Step-by-step explanation:
is the first choice, no other terms have anything in common with the number
399 or variable w
Luke works at a shoe store. He earns a 2% commission on all shoes he sells. If he sells $50 of shoes, how much money will he make with his commission?
Answer:
$1
Step-by-step explanation:
Commission earned on sale = 2%
Total sales made = $50
Commission earned for this sale :
Commission percent * worth of sales made
0.02 * $50
= $1
The dance team has three cupcake sales a
year to raise money. The amount of money
they make is a function of the amount of
people who buy cupcakes. This function is
represented by the three ordered pairs (40,
100), (70, 175) and (90, 225). What is the
domain of this function?
help
Answer:
40,70,90
Step-by-step explanation:
There were 239 people at a Travis Scott concert. Admission to the drive-in concert was $15 for adults and $5.50 for children. The total cost was $2758.50.
Part A: Set up a system of equations.
Solve the system of equations algebraically. SHOW ALL WORK!
How many adults attended? How many children attended?
(i need it asap pleaseeeee)
Please help! I need help on this ! I will give brainliest!
Find the equation of a line that is parallel to the line x = 12 and contains the point (-6,4).
The equation of the parallel line is . (Type an equation.)
Answer:
x = -6 and x = 12 are parallel
Step-by-step explanation:
they are both vertical lines, one crosses the x-axis at -6, the other at 12
Which equation could generate the curve in a graph below?
What is the value of the expression below? 52 + (8 – 6)
Answer:
54
Step-by-step explanation:
Graph the direct variation that includes the point (5,4). write the equation of the line.
How do I solve this?
Answer:u have to be missing something
Step-by-step explanation:
Answer:
does the question have a graph or is it just the word problem?
here is the answer if its just the word problem
Step-by-step explanation:
y= -5x+4
hope I helped :)
Consider the line y=5x-3.
Find the equation of the line that is parallel to this line and passes through the point (2, -5).
Find the equation of the line that is perpendicular to this line and passes through the point (2, -5).
Answer:
y=5x-15, y=-1/5x-23/5
Step-by-step explanation:
Parallel lines have the same slope, so we know the line that is parallel to y=5x-3 must have slope 5.
We now have y=5x+b. We are given the point (2, -5) so substitute the x and y coordinates into the equation.
y=5x+b
-5=5(2)+b
-5=10+b
b=-15
So the equation of the parallel line is y=5x-15.
Perpendicular lines must have slopes that multiply to -1, so we know the line perpendicular to y=5x-3 must have slope -1/5.
We now have y=-1/5x+b. We are given the point (2, -5) so substitute the x and y coordinates into the equation.
y=-1/5x+b
-5=-1/5(2)+b
-5=-2/5+b
b=-23/5
So the equation of the perpendicular line is y=-1/5x-23/5.
What’s the zero of the function on the graph PLEASE
Answer:
B) x = -5
Step-by-step explanation:
The zero of a graph is the inputted value in which the output is 0. Therefore, we must find the x-value that makes the y-value be 0. In the graph, we see that y = 0 at (-5, 0). The x-value of the coordinate (-5, 0) is -5. Therefore, the zero of the function in the graph is x = -5.
I hope this helps! :)
What does the arrow represent?
Bouncing a Ball Height ha 0 Time
a. the ball is hitting the ground for the first time
b. the ball has hit the ground for the third time and is rising
c. the ball has reaches the maximum height of the first bounce
d. the ball has been thrown and is traveling towards the ground
Answer:
b number is the correct answer of the question
Answer:its a
a
Step-by-step explanation:
Jada has read 3/5 of a book. She read 75 pages so far. How many pages are in the whole book
Step-by-step explanation:
3/5 of the book = 75 pages
5/5 of the book = 75 * (5/3) = 125 pages
Hence there are 125 pages in the whole book.
Answer:
Concept: Data Analysis
Jada has read 60% of the book So 60% of the book is 75 pages We want to find the whole count of pages An easy way to do this is to see that for every 20% you have 15 pages You need 40% So its 30 pages So 75+30= 105 pages(14)/(5)=(x)/(25) please help
Step-by-step explanation:
(14)/(5)=(x)/(25)
We move all terms to the left:
(14)/(5)-((x)/(25))=0
We add all the numbers together, and all the variables
-(+x/25)+14/5=0
We get rid of parentheses
-x/25+14/5=0
We calculate fractions
There is no solution for this equation
-5b = -20 b= need help with homwork
Answer:
b = 4
Step-by-step explanation:
you must divide both sides of the equation by -5 to get b by itself. division cancels out multiplication but also keeps both sides equal
b = -20/-5
b = 4