On his most recent math test, Jeremy answered 48 questions correct out of 80 total questions. Which statement can be made about Jeremy's math test?

Answer:

δw/δr = 4π

δw/δθ = -8π

Step-by-step explanation:

Given the following functions

w = xy + yz + zx, x = r cosθ y = r sinθ, z = rθ where r = 4 and θ = π/2

We are to find δw/δr and δw/δθ

δw/δr = δw/δx•δx/δr + δw/δy•δy/δr + δw/δz•δz/δr

δw/δx = y+z

δx/δr = cosθ

δw/δy = x+z

δy/δr = sinθ

δw/δz = y+x

δz/δr = θ

Substitute the given values into the formula

δw/δr = (y+z)cosθ+(x+z)sinθ+(y+x)θ

Substitute the value of x, y and z in terms of theta into the resulting function

δw/δr = (y+z)cosθ+(x+z)sinθ+(y+x)θ

δw/δr = (rsinθ+rθ)cosθ+(rcosθ+rθ)sinθ+(rsinθ+rcosθ)θ

Substitute r = 4 and θ = π/2

δw/δr = (4sinπ/2+4π/2)cosπ/2+(4cosπ/2+4π/2)sinπ/2+(4sinπ/2+4cosπ/2)π/2

Note that cos π/2 = 0 and sinπ/2 = 1

δw/δr = (4+2π)(0)+(0+2π)(1)+(4(1)+4(0))π/2

δw/δr = 0+2π+4π/2

δw/δr = 2π+2π

δw/δr = 4π

For δw/δθ

δw/δθ = δw/δx•δx/δθ + δw/δy•δy/δθ + δw/δz•δz/δθ

δw/δx = y+z

δx/δθ = -rsinθ

δw/δy = x+z

δy/δθ =rcosθ

δw/δz = y+x

δz/δθ = r

Substitute the given values into the formula

δw/δθ = (y+z)-rsinθ+(x+z)rcosθ+(y+x)r

Substitute the value of x, y and z in terms of theta into the resulting function

δw/δθ = (y+z)-rsinθ+(x+z)rcosθ+(y+x)r

δw/δθ = (rsinθ+rθ)-rsinθ+(rcosθ+rθ)rcosθ+(rsinθ+rcosθ)r

Substitute r = 4 and θ = π/2

δw/δθ = (4sinπ/2+4π/2)-4sinπ/2+(4cosπ/2+4π/2)4cosπ/2+(4sinπ/2+4cosπ/2)(4)

Note that cos π/2 = 0 and sinπ/2 = 1

δw/δθ = (4+2π)(-4)+(0+2π)(0)+(4(1)+4(0))(4)

δw/δθ = -16-8π+0+4(4)

δw/δθ = -16+16-8π

δw/δθ = -8π

Answer:

He has been saving for 41 weeks.

Step-by-step explanation:

492 is the total, we need to divide 492 by 12 to get how many weeks, 41 is the answer

Answer:

[tex]r = 1.34[/tex]

Step-by-step explanation:

Given

Solid = Cylinder + 2 hemisphere

[tex]Volume = 10cm^3[/tex]

Required

Determine the radius (r) that minimizes the surface area

First, we need to determine the volume of the shape.

Volume of Cylinder (V1) is:

[tex]V_1 = \pi r^2h[/tex]

Volume of 2 hemispheres (V2) is:

[tex]V_2 = \frac{2}{3}\pi r^3 +\frac{2}{3}\pi r^3[/tex]

[tex]V_2 = \frac{4}{3}\pi r^3[/tex]

Volume of the solid is:

[tex]V = V_1 + V_2[/tex]

[tex]V = \pi r^2h + \frac{4}{3}\pi r^3[/tex]

Substitute 10 for V

[tex]10 = \pi r^2h + \frac{4}{3}\pi r^3[/tex]

Next, we make h the subject

[tex]\pi r^2h = 10 - \frac{4}{3}\pi r^3[/tex]

Solve for h

[tex]h = \frac{10}{\pi r^2} - \frac{\frac{4}{3}\pi r^3 }{\pi r^2}[/tex]

[tex]h = \frac{10}{\pi r^2} - \frac{4\pi r^3 }{3\pi r^2}[/tex]

[tex]h = \frac{10}{\pi r^2} - \frac{4r }{3}[/tex]

Next, we determine the surface area

Surface area (A1) of the cylinder:

Note that the cylinder is covered by the 2 hemisphere.

So, we only calculate the surface area of the curved surface.

i.e.

[tex]A_1 = 2\pi rh[/tex]

Surface Area (A2) of 2 hemispheres is:

[tex]A_2 = 2\pi r^2+2\pi r^2[/tex]

[tex]A_2 = 4\pi r^2[/tex]

Surface Area (A) of solid is

[tex]A = A_1 + A_2[/tex]

[tex]A = 2\pi rh + 4\pi r^2[/tex]

Substitute [tex]h = \frac{10}{\pi r^2} - \frac{4r }{3}[/tex]

[tex]A = 2\pi r(\frac{10}{\pi r^2} - \frac{4r }{3}) + 4\pi r^2[/tex]

Open bracket

[tex]A = \frac{2\pi r*10}{\pi r^2} - \frac{2\pi r*4r }{3} + 4\pi r^2[/tex]

[tex]A = \frac{2*10}{r} - \frac{2\pi r*4r }{3} + 4\pi r^2[/tex]

[tex]A = \frac{20}{r} - \frac{8\pi r^2 }{3} + 4\pi r^2[/tex]

[tex]A = \frac{20}{r} + \frac{-8\pi r^2 }{3} + 4\pi r^2[/tex]

Take LCM

[tex]A = \frac{20}{r} + \frac{-8\pi r^2 + 12\pi r^2}{3}[/tex]

[tex]A = \frac{20}{r} + \frac{4\pi r^2}{3}[/tex]

Differentiate w.r.t r

[tex]A' = -\frac{20}{r^2} + \frac{8\pi r}{3}[/tex]

Equate A' to 0

[tex]-\frac{20}{r^2} + \frac{8\pi r}{3} = 0[/tex]

Solve for r

[tex]\frac{8\pi r}{3} = \frac{20}{r^2}[/tex]

Cross Multiply

[tex]8\pi r * r^2 = 20 * 3[/tex]

[tex]8\pi r^3 = 60[/tex]

Divide both sides by [tex]8\pi[/tex]

[tex]r^3 = \frac{60}{8\pi}[/tex]

[tex]r^3 = \frac{15}{2\pi}[/tex]

Take [tex]\pi = 22/7[/tex]

[tex]r^3 = \frac{15}{2 * 22/7}[/tex]

[tex]r^3 = \frac{15}{44/7}[/tex]

[tex]r^3 = \frac{15*7}{44}[/tex]

[tex]r^3 = \frac{105}{44}[/tex]

Take cube roots of both sides

[tex]r = \sqrt[3]{\frac{105}{44}}[/tex]

[tex]r = \sqrt[3]{2.38636363636}[/tex]

[tex]r = 1.33632535155[/tex]

[tex]r = 1.34[/tex] (approximated)

Hence, the radius is 1.34cm

The radius of the cylinder that produces the minimum surface area is 1.34cm and this can be determined by using the formula area and volume of cylinder and hemisphere.

Given :

The volume of a cylinder is given by:

[tex]\rm V = \pi r^2 h[/tex]

The total volume of the two hemispheres is given by:

[tex]\rm V' = 2\times \dfrac{2}{3}\pi r^3[/tex]

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

Now, the total volume of the solid is given by:

[tex]\rm V_T = \pi r^2 h+\dfrac{4}{3}\pi r^3[/tex]

Now, substitute the value of the total volume in the above expression and then solve for h.

[tex]\rm 10 = \pi r^2 h+\dfrac{4}{3}\pi r^3[/tex]

[tex]\rm h = \dfrac{10}{\pi r^2}-\dfrac{4r}{3}[/tex]

Now, the surface area of the curved surface is given by:

[tex]\rm A = 2\pi r h[/tex]

Now, the surface area of the two hemispheres is given by:

[tex]\rm A'=2\times (2\pi r^2)[/tex]

[tex]\rm A'=4\pi r^2[/tex]

Now, the total area is given by:

[tex]\rm A_T = 2\pi rh+4\pi r^2[/tex]

Now, substitute the value of 'h' in the above expression.

[tex]\rm A_T = 2\pi r\left(\dfrac{10}{\pi r^2}-\dfrac{4r}{3}\right)+4\pi r^2[/tex]

Simplify the above expression.

[tex]\rm A_T = \dfrac{20}{r} + \dfrac{4\pi r^2}{3}[/tex]

Now, differentiate the total area with respect to 'r'.

[tex]\rm \dfrac{dA_T}{dr} = -\dfrac{20}{r^2} + \dfrac{8\pi r}{3}[/tex]

Now, equate the above expression to zero.

[tex]\rm 0= -\dfrac{20}{r^2} + \dfrac{8\pi r}{3}[/tex]

Simplify the above expression in order to determine the value of 'r'.

[tex]8\pi r^3=60[/tex]

r = 1.34 cm

For more information, refer to the link given below:

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Answer:

y= 4 x  

Step-by-step explanation:

y =4x − 7

Choose a point that the parallel line will pass through.

(0 , 0 )

Use the slope-intercept form to find the slope.

Tap for fewer steps...

The slope-intercept form is  

y = m x+ b , where  m  is the slope and b  is the y-intercept. y = m x + b

Using the slope-intercept form, the slope is  

4 . m = 4

To find an equation that is parallel to  y = 4 x − 7 , the slopes must be equal. Using the slope of the equation, find the parallel line using the point-slope formula.

( 0 , 0 ) m = 4

Using the point-slope form  

y − y 1 = m ( x −x 1 ) , plug in  m = 4 ,  x 1 = 0 , and  y 1 = 0 .

y − ( 0 ) = ( 4 )( x − ( 0 ) )

Solve for  y.

Subtract  0  from  y .

y = ( 4 ) ( x − ( 0 ) )

Subtract  0  from  x .

y= 4 x  

HOPE THIS HELPS!

pLEASE MARK bRAINLIEST! :)

Answer:

A)

534 rounds to 500

395 rounds to 400

B) 100

Step-by-step explanation:

A)

534 rounds to 500 because the next digit 3 is less than 5 which means that you round down.

395 rounds to 400 because the next digit 9 is greater than 5 which means that you round up.

B)

500-400=100

Hope this helps! :)

Answer:

Yes! (it’s making me write 20 letters so yes is ur answer ok cool)

Answer:

show me the choices

Step-by-step explanation:

so i qnswer ir

Answer:

b

Step-by-step explanation:

it is 3 out of 5 ticks over to the left

largest 4 digit number : 9999

smallest 4 digit numbers : 1000

Difference = 9999 - 1000 = 8999

Answer:

Step-by-step explanation:

huh??

Answer:

6 + 10v – 8w = 62

Step-by-step explanation:

Given the expression

6 + 10v – 8w

as

substituting the values in the expression

6 + 10v – 8w = 6 + 10(4) - 8(-2)

                      = 6 + 40 + 16

                      = 62

Answer:

Step-by-step explanation:

holdup im gonna help

Answer:

x = 2

Step-by-step explanation:

2[3(3x - 1)] = 5(2x + 2)

18x - 6 = 10x + 10

8x = 16

x = 2

Answer:

domain (-∞, ∞)

range [-3,∞)

Step-by-step explanation:

domain is the x value and range is the y value. Since its an absolute value the y value rises from both sides of the x value in a 45° angle.

Answer:

1082.99

Step-by-step explanation:

2927 - 100%;

x - 37%;

=> x = (37*2927)/100 = 1082.99

(13−0)

           = 10/13

(10−0)

​13,10

Slope of the given line is [tex]\frac{10}{13}[/tex] and the equation of the line is [tex]10x - 13y = 0[/tex].

The slope of a line(m) that passes through points (x, y) and (x, y) is

[tex]m = \frac{y_{2} - x_{1}}{x_{2} - x_{1}}[/tex]

The given line passes through points (0, 1.3) and (0, 1).

Therefore, slope of the line is

[tex]m = \frac{y_{2} - x_{1}}{x_{2} - x_{1}} = \frac{1 - 0}{1.3 - 0} = \frac{10}{13}[/tex]

Now, the line passes through the point (2.6, 2).

Putting this equation in slope-intercept form, we get:

[tex]2 = \frac{10}{13}(2.6) + c\\c = 2 - 2\\c = 0[/tex]

The equation of the line will be:

[tex]y = \frac{10}{13}x\\10x - 13y = 0[/tex]

Learn more about slope of a line here: https://brainly.com/question/21504186

#SPJ3

Answer:

-.1

Step-by-step explanation:

Answer:C

1/1+cos(x)

Step-by-step explanation:

Simplifird form of the given trigonometric expression will be,

         [sinx / (1 - cos²x)] × tan(x/2) = 1 /(1 + cosx)

Given expression in the question,

[tex]\frac{\text{sinx}}{1-\text{cos}^2x}\times \text{tan}(\frac{x}{2})[/tex]

= [tex]\frac{\text{sinx}}{\text{sin}^2x}\times \text{tan}(\frac{x}{2} )[/tex]

= [tex]\frac{1}{\text{sin}x}\times \frac{\text{sin}(\frac{x}{2})}{\text{cos}(\frac{x}{2} )}[/tex]

= [tex]\frac{1}{\text{2sin}\frac{x}{2}\text{cos}(\frac{x}{2} ) }\times \frac{\text{sin}(\frac{x}{2})}{\text{cos}(\frac{x}{2} )}[/tex]

= [tex]\frac{1}{\text{2cos}^2{\frac{x}{2} }}[/tex]

Use the identity → ([tex]2\text{cos}^2x=1+\text{cosx}[/tex])

= [tex]\frac{1}{1+\text{cos}x}[/tex]        

          Hence, [tex]\frac{\text{sinx}}{1-\text{cos}^2x}\times \text{tan}(\frac{x}{2})=\frac{1}{1+\text{cosx}}[/tex] will be the answer.

Learn more to simplify the trigonometric expressions here,

https://brainly.com/question/17043514?referrer=searchResults

Answer:

Step-by-step explanation:

Distributive property, subtraction, division

4(2x + 3) = 10x

8x + 12 = 10x

12 = 2x

6 = x

Answer:

x=22

Step-by-step explanation:

3x+3+27+x+3+2x+18=180

6x+48=180

6x=132

x=22

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[tex]y = f(x) = 2x + 5[/tex]

[tex]f(2) = 2(2) + 5[/tex]

[tex]f(2) = 4 + 5[/tex]

[tex]f(2) = 9[/tex]

Thus ;

[tex]( \: 2 \: , \: 9 \: )[/tex]

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Answer:

9

Step-by-step explanation:

Answer:

A) f(x) = 0.85x

B) g(x) = x - 1500

C) g(f(x)) = $14650

D) f(g(x)) = $14875

Step-by-step explanation:

A) The list price is x and a 15% discount is applied.

Thus;

f(x) = x - 15%x

f(x) = 0.85x

B) We are told that the manufacturer offers a $1500 rebate for each purchase of a car.

Thus, the function g(x) to represent the price after the rebate is applied is;

g(x) = x - 1500

C)if the discount is applied before the rebate, the function is;

g(f(x))

Now,

f(x) = 0.85(19000)

f(x) = 16150

g(x) = x - 1500

Thus;

g(x) = 16150 - 1500

g(x) = $14650

D) If discount after rebate, then we have; f(g(x))

g(x) = 19000 - 1500

g(x) = 17500

f(g(x)) = 0.85(17500)

f(g(x)) = $14875

===================================================

Explanation:

Choice B is one answer because -2 and 2 are additive inverses that add to -2+2 = 0

Choice D is a similar story. We have -5+5 = 0

In general, if x is some number then -x is its additive inverse. So we can say x+(-x) = 0 or -x+x = 0. In short, additive inverses add to 0.

Answer:

B and D

Step-by-step explanation:

Answer:

130

Step-by-step explanation:

Ratio is 2:5:3. Colin get 2/10 of the sweets so 26/x=2/10. Use the butterfly method to get 260=2x. Divide both sides by 2 and get x=130/

Answer:

$2734

Step-by-step explanation:

$98,424 / 36 = $2734