A wooden log 10 meters long is leaning against a vertical wall with its other end on the ground. The top end of the log is sliding down the wall. When the top end is 6 meters from the ground, it slides down at 2m/sec. How fast is the bottom moving away from the wall at this instant?

Answers

Answer 1

Answer:

Step-by-step explanation:

This is a related rates problem from calculus using implicit differentiation. The main equation is Pythagorean's Theorem. Basically, what we are looking for is [tex]\frac{dx}{dt}[/tex] when y = 6 and [tex]\frac{dy}{dt}=-2[/tex].

The equation for Pythagorean's Theorem is

[tex]x^2+y^2=c^2[/tex] where x and y are the legs and c is the hypotenuse. The length of the hypotenuse is 10, so when we find the derivative of this function with respect to time, and using implicit differentiation, we get:

[tex]2x\frac{dx}{dt}+2y\frac{dy}{dt}=0[/tex] and divide everything by 2 to simplify:

[tex]x\frac{dx}{dt}+y\frac{dy}{dt}=0[/tex]. Looking at that equation, it looks like we need a value for x, y, [tex]\frac{dx}{dt}[/tex] and [tex]\frac{dy}{dt}[/tex].

Since we are looking for [tex]\frac{dx}{dt}[/tex], that can be our only unknown and everything else has to have a value. So what do we know?

If we construct a right triangle with 10 as the hypotenuse and use 6 for y, we can solve for x (which is the only unknown we have, actually). Using Pythagorean's Theorem to solve for x:

[tex]x^2+6^2=10^2[/tex] and

[tex]x^2+36=100[/tex] and

[tex]x^2=64[/tex] so

x = 8.

NOW we can fill in the derivative and solve for [tex]\frac{dx}{dt}[/tex].

Remember the derivative is

[tex]x\frac{dx}{dt}+y\frac{dy}{dt}=0[/tex] so

[tex]8\frac{dx}{dt}+6(-2)=0[/tex] and

[tex]8\frac{dx}{dt}-12=0[/tex] and

[tex]8\frac{dx}{dt}=12[/tex] so

[tex]\frac{dx}{dt}=\frac{12}{8}=\frac{6}{4}=\frac{3}{2}=1.5 m/sec[/tex]


Related Questions

PLZ ANSWER ASAP
(look at images below, from khan)

Answers

Answer:

D Replace on equation with sum /difference of both equations

The systems are still the same

Step-by-step explanation:

5x + y = 3

4x - 7y = 8

Subtract the second equation from the first

5x + y = 3

-(4x - 7y = 8)

-----------------

x    +8y = -5

The second equation in system B is the first equation in system a minus the second equation in system A

We added the same thing to each side of the equation so the the system is still the same

the best answer would be d

On a map, the scale shown is 1 inch : 5 miles. If an island is 2.5 squire inches on the map, what is the actual area of the island? The actual island's area is square miles.​

Answers

Answer:

62.5 square miles

Step-by-step explanation:

if the scale is 1 in. = 5 mi, then 1 square in. = 25 square miles

so if 1 in^2 = 25 mi^2

then you make a proportion

25/1 = x/2.5

(the square inches on the bottom and the square miles on top)

solving for x gives you

x=62.5 square miles

Instructions: Given the vertex of a quadratic function, find the axis
of symmetry.
Vertex: (5,7)

Answers

Taking into account the definition of axis of simmetry and vertexn the axis of symmetry is x = 5.

So, first of all, you must know what a quadratic function is. Every quadratic function can be expressed as follows:

f(x) = a*x² + b*x + c

where a, b and c are real numbers.

Axis of symetry

The graph of a quadratic function is a parabola. Every parabola is a symmetric curve with respect to a horizontal line called the axis of symmetry.

That is, the axis of symmetry is an imaginary line that passes through the middle of the parabola and divides it into two halves that are equal of each other.

In other words, the axis of symmetry of a parabola is a vertical line that divides the parabola into two equal halves and always passes through the vertex of the parabola.

Vertex

The point of intersection of the axis of symmetry with the parabola is called the vertex.

The axis of symmetry always passes through the vertex of the parabola. The x-coordinate of the vertex is the equation of the axis of symmetry of the parabola.

Summary

Being the vertex of the quadratic function (5,7), where the vertex on the x-axis has a value of 5 and on the y-axis a value of 7, the axis of symmetry is x = 5.

Learn more with this examples:

https://brainly.com/question/2799442?referrer=searchResultshttps://brainly.com/question/20862832?referrer=searchResultshttps://brainly.com/question/15266651?referrer=searchResults

Which of the following methods of sampling is an example of a stratified random sample?

A. Randomly choosing a name from a list of names in the population and then choosing every tenth name thereafter.
B. From 500 names of members of a population in a hat drawing 50 names from the hat without looking.
C. Dividing a target population of students by grade level and choosing the first 25 names from each group.
D. Dividing a population of adults into males and females and randomly choosing a sample proportional to the numbers in each group.

Answers

Answer: D

Step-by-step explanation:

Answer: D

Step-by-step explanation:

of a loaf of brown bread costs R6, how much will 4 halves cost?​

Answers

Answer:

R12

Step-by-step explanation:

Answer: R12

Explanation:

Cost of 1 loaf = R6

Cost of 4 halves = 6/2×4

= 6 × 2

= R12

Please click thanks and mark brainliest if you like

What is 20×10 to the third power equal

Answers

Answer:

20000

Step-by-step explanation:

Your equation will look like this to the third power:

20 x 10^3

Step 1. Solve for 10^3

Answer: 1000

Step 2. Multiply 20 x 1000

Answer: 20000

A basic cellular package costs $30/month for 60 minutes of calling with an additional charge of $0.40/minute beyond that time. The cost function C (2) for using x minutes would be • If you used 60 minutes or less, i.e. if if x < 60, then C (x) = 30 (the base charge). If you used more than 60 minutes, i.e. (x – 60 minutes more than the plan came with, you would pay an additional $0.40 for each of those (x – 60 minutes. Your total bill would be C (x) = 30 + 0.40 (x – 60). If you want to keep your bill at $50 or lower for the month, what is the maximum number of calling minutes you can use? minutes. The maximum calling minutes you can use is ? Number​

Answers

Answer:

The maximum number of minutes to keep the cost at $50 or less is 110 minutes

Step-by-step explanation:

Given

[tex]C(x) = 30[/tex] ---- [tex]x < 60[/tex]

[tex]C(x) = 30 + 0.40(x - 60)[/tex] --- [tex]x \ge 60[/tex]

Required

[tex]C(x) = 50[/tex] ---- find x

We have:

[tex]C(x) = 30 + 0.40(x - 60)[/tex]

Substitute 50 for C(x)

[tex]50 = 30 + 0.40(x - 60)[/tex]

Subtract 30 from both sides

[tex]20 = 0.40(x - 60)[/tex]

Divide both sides by 0.40

[tex]50 = x - 60[/tex]

Add 60 to both sides

[tex]110 = x[/tex]

[tex]x =110[/tex]

Which of the following is correctly written in Standard Form? −3x + 7y = 12, y = 3/7x + 6 ,5x − 4y = 9 ,3/7x + 2y =9

Answers

2nd one - y = 3/7x + 6 , hope this helps:)

10) Find three numbers whose product is -72. You may use integers from -10 to 10. Give two
examples

Answers

Answer:

Step-by-step explanation:

-8 *  9 * 1

If you are going to get - 72, you need to have an odd number of minus signs.

4 * 3 * - 6

You must be careful of the limits. You can't use something like 36 * 2  * 1 because the numbers don't fall within +/- 10

You could use 6*6*-2

Simplify the algebraic expression by combining like (or similar) terms.

2x−y2+3−3y2+2x+1

Answers

Answer:

-4y^2 + 4x +4

Step-by-step explanation:

add -y^2 and -3y^2 = -4y^2

add 2x + 2x = 4x

add 3+1 = 4

and then rearrange

the polygons in each pair are similar find the scale factor smaller figure to the larger

Answers

Answer:

smaller figure/larger figure = ½

Step-by-step explanation:

The scale factor = any of the side length of the smaller figure / the corresponding side length of the larger figure

Side length of smaller figure = 3

Corresponding sides length of larger figure = 6

Scale factor = smaller figure/larger figure = 3/6

Simplify

Scale factor = smaller figure/larger figure = ½

Please help with Question 2b

Answers

Answer:

MUST BE IN HLA, NOT FROM C TO ASSEMBLY.

PROGRAM 6: Same

Write an HLA Assembly language program that implements a function which correctly identifies when all four parameters are the same and returns a boolean value in AL (1 when all four values are equal; 0 otherwise). This function should have the following signature:

procedure theSam

Diana get a gift card with a value of $55, and her favorite drink cost $2.20. How many plain black coffee can she buy with the gift card

Answers

Answer:

Twouufyjughgyuioiu567uhu888

Answer:

55/2.20=25 so 25 black coffees

Step-by-step explanation:

Can someone please help with 25 , please put the way you got it. Please no links it’s serious

Answers

Answer:

X * 0.8 = $64

x = $80

Step-by-step explanation:

strontium-90 is a radioactive material that decays according to the function A(t)=A0e−0.0244t, where A0 is the initial amount present and A is the amount present at time t​ (in years). Assume that a scientist has a sample of 400 grams of​ strontium-90. ​
(a) What is the decay rate of​ strontium-90?
​(b) How much​ strontium-90 is left after 30 ​years?
​(c) When will only 100 grams of​ strontium-90 be​ left?
​(d) What is the​ half-life of​ strontium-90?

​(a) The decay rate of​ strontium-90 is nothing​%.
​(Type an integer or a decimal. Include the negative sign for the decay​ rate.)

Answers

Answer:

Step-by-step explanation:

The decay rate of strontium-90 is -.0244 as given.

For b., we have to use the formula to find out how much is left after 30 years. This will be important for part d.

[tex]A(t)=400e^{-.0244(30)}[/tex] which simplifies a bit to

A(t) = 400(.4809461353) so

A(t) = 192.4 g

For c., we have to find out how long it takes for the initial amount of 400 g to decay to 100:

[tex]100=400e^{-.0244t}[/tex]. Begin by dividing both sides by 400:

[tex].25=e^{-.0244t[/tex] and then take the natural log of both sides:

[tex]ln(.25)=lne^{-.0244t[/tex] . The natural log and the e cancel each other out since they are inverses of one another, leaving us with:

ln(.25) = -.0244t and divide by -.0244:

61.8 years = t

For d., we figured in b that after 30 years, 192.4 g of the element was left, so we can use that to solve for the half-life in a different formula:

[tex]A(t)=A_0(.5)^{\frac{t}{H}[/tex] and we are solving for H. Filling in:

[tex]192.4=400(.5)^{\frac{30}{H}[/tex] and begin by dividing both sides by 400:

[tex].481=(.5)^{\frac{30}{H}[/tex] and take the natural log of both sides, which allows us to pull the exponent out front. I'm going to include that step in with this one:

ln(.481) = [tex]\frac{30}{H}[/tex] ln(.5) and then divide both sides by ln(.5):

[tex]\frac{ln(.481)}{ln(.5)}=\frac{30}{H}[/tex] and cross multiply and isolate the H to get:

[tex]H=\frac{30ln(.5)}{ln(.481)}[/tex] and

H = 28.4 years

Use the distributive property to simplify
the equation below.
с
8(2a + 4b - c)
[? ]a + [ ]b - [
[ ]

Answers

Answer:

16a +32b - 8c

Step-by-step explanation:

8(2a + 4b - c)

Distribute

8*2a  + 8*4b+ 8*(-c)

16a +32b - 8c

Answer:

16a + 32b - 8c

Step-by-step explanation:

You bring 8 inside the parenthesis and then multiply it with everything. so for a you put 16, b you put 32 and c you put 8

What is the equation of this graph

Answers

Answer:

y-1=x^2

Step-by-step explanation:

That is the equation of a parabola with vertex at (0,1). The equation is y-1=x^2.

Air is being pumped into a spherical balloon at a rate of 5 cm^3/min. Determine the rate at which the radius of the balloon is increasing when the diameter of the balloon is 20 cm

Answers

0.08 cm/min

Step-by-step explanation:

Given:

[tex]\dfrac{dV}{dt}=5\:\text{cm}^3\text{/min}[/tex]

Find [tex]\frac{dr}{dt}[/tex] when diameter D = 20 cm.

We know that the volume of a sphere is given by

[tex]V = \dfrac{4\pi}{3}r^3[/tex]

Taking the time derivative of V, we get

[tex]\dfrac{dV}{dt} = 4\pi r^2\dfrac{dr}{dt} = 4\pi\left(\dfrac{D}{2}\right)^2\dfrac{dr}{dt} = \pi D^2\dfrac{dr}{dt}[/tex]

Solving for [tex]\frac{dr}{dt}[/tex], we get

[tex]\dfrac{dr}{dt} = \left(\dfrac{1}{\pi D^2}\right)\dfrac{dV}{dt} = \dfrac{1}{\pi(20\:\text{cm}^2)}(5\:\text{cm}^3\text{/min})[/tex]

[tex]\:\:\:\:\:\:\:= 0.08\:\text{cm/min}[/tex]

Larry made 14 baskets out of 21 attempts in a recent basketball game. If Scott attempted 24 baskets and made the same proportion of baskets as Larry, how many baskets did Scott make?

Scott made
baskets.

Answers

Answer:

16 baskets

Step-by-step explanation:

Create a proportion where x is the number of baskets that Scott made:

[tex]\frac{14}{21}[/tex] = [tex]\frac{x}{24}[/tex]

Cross multiply and solve for x:

21x = 336

x = 16

So, Scott made 16 baskets.

What is lim j(x)?
X-3

Answers

9514 1404 393

Answer:

  (b)  4

Step-by-step explanation:

The point (3, 4) is a "hole" in the graph. The function approaches the value y=4 from either direction, so that is the limit as x → 3.

  [tex]\displaystyle\lim_{x\to3}f(x)=4[/tex]

What are the values of a, b, and c in the quadratic equation 0 = one-halfx2 – 3x – 2?

a = one-half, b = 3, c = 2
a = one-half, b = –3, c = –2
a = one-half, b = 3, c = –2
a = one-half, b = –3, c = 2

Answers

Answer:

b

Step-by-step explanation:

ax^2+bx+c=0

1/2x^2-3x-2=0

Answer:

B

Step-by-step explanation:

I need help with the answer

Answers

Answer:

Option B, x ≈ -2.25

Step-by-step explanation:

3^x-2=(x-1)/(x^2+x-1)

or x ≈ -2.21166

so it's closest to the answer of the 2nd option

Factorize p2-15q-5p+2pq​

Answers

Hope it's help you!!!!!!

Find the value of x.
A. 4
B. 2
C. 3
D. 6

Answers

Answer:

b

Step-by-step explanation:

2x4=8 3x2=6 2x2=4

there all diviseble by 2

therfore ur answer is b

Answer:

the answer is 4

Step-by-step explanation:

Find the remainder when f(x)=x3−4x2−6x−3 f ( x ) = x 3 − 4 x 2 − 6 x − 3 is divided by x+1

Answers

Answer:

The remainder is -2.

Step-by-step explanation:

According to the Polynomial Remainder Theorem, if we divide a polynomial P(x) by a binomial (x - a), then the remainder of the operation will be given by P(a).

Our polynomial is:

[tex]P(x) = x^3-4x^2-6x-3[/tex]

And we want to find the remainder when it's divided by the binomial:

[tex]x+1[/tex]

We can rewrite our divisor as (x - (-1)). Hence, a = -1.

Then by the PRT, the remainder will be:

[tex]\displaystyle\begin{aligned} R &= P(-1)\\ &=(-1)^3-4(-1)^2-6(-1)-3 \\ &= (-1)-4(1)+(6)-3 \\ &= -2 \end{aligned}[/tex]

The remainder is -2.

The probability of winning a raffle is 2/5. What is the probability of not winning the raffle?

0
3/5
2/5

Answers

Answer:

3/5

Step-by-step explanation:

um 3/5+2/5 = 1

Which graph has the solutions -1 and 4?
a.
On a coordinate plane, a parabola opens up and goes through (negative 4.2, 0) and (0, negative 1).
c.
On a coordinate plane, a parabola opens up and goes through (negative 4, 0) and (1, 0).
b.
On a coordinate plane, a parabola opens up and goes through (0, negative 3) and (4.5, 0).
d.
On a coordinate plane, a parabola opens up and goes through (0, negative 1) and (4, 0).



Please select the best answer from the choices provided


A
B
C
D

Answers

Answer:

graph d

in graph d, the line intersects the x axis twice at (-1,0) and (4,0), so those two are the solutions of the graph

Hi! I would appreciate if you could solve this for me. The question I need help with is question 41. Thank you. :)

Answers

Answer:

Expression: 7+7+9.5+6+9.5

Evaluation: 39 cm

Step-by-step explanation:

Let's write the numerical expression for the figure to the right. The perimeter is the addition of all sides of the figure. Therefore, we write 7+7+9.5+6+9.5 for our expression.

Now, to evaluate the expression, we just add them together. 7+7+9.5+6+9.5=39 cm.

Example 2.20
Solution
After 7% discount, Faizal get RM1,930 from a bank. He then promised to pay the bank RM2,000
after x days. Determine the value of x.
Kaspersk
Th​

Answers

The period of days (value of x) for which Faizal promised to pay the bank RM 2,000 after getting 7% discounted present value of RM 1,930 is 180 days.

The value of x is the period of days (number of days) that the loan from the bank will last before Faizal, who received RM 1,930 discounted at 7%, would repay the bank the principal and interest of RM 2,000.

This implies that Faizal is paying an interest of RM 70 (RM 2,000 - RM 1,930), since he borrowed RM 1,930 and will repay RM 2,000.

Data and Calculations:

Present value of loan received = RM 1,930

Discount rate per year = 7%

Future value of the loan to be repaid to the bank = RM 2,000

Interest expense for one year based on 7% = RM 140 (RM 2,000 x 7%)

Interest expense for 180 days or 6 months = RM 70 (RM 2,000 - RM 1,930) or (RM 2,000 x 7%) x 180/360

Interest expense that equals RM 70 will be half of a year or 180 days (RM 140 * 180/360)

Thus, the period of days (x) that will lapse for Faizal to repay the bank is 180 days or half of a year (6 months).

Learn more about time period of a loan here: https://brainly.com/question/19118285

A painter can paint 36 feet of molding per hour. How many inches of molding can he paint per hour?

Answers

Answer:

432 inches

Step-by-step explanation:

We need to convert feet to inches

1 ft = 12 inches

36 ft * 12 inches/ 1 ft = 432 inches

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