Estimate the difference of the decimals below by rounding to the nearest whole number 42.706

Surface area of solid figures

Lilit [14]

Answer:

C. 468mm²

Step-by-step explanation:

The formula for the surface area of rectangular prism is:

$A=2(wl+hl+hw)$

Let's break down our variables.

L = 12mm

W = 6mm

H = 7mm + 2mm = 9mm

Now we substitute our values in the formula:

$A=2((6)(12)+(9)(12)+(9)(6))$

$A=2(72+108+54)$

$A=2(234)$

$A=468mm^{2}$

6 0

2 years ago

Can someone please help me with this

vaieri [72.5K]

Answer:4 in each package

Step-by-step explanation:

3 0

2 years ago

The plane x + y + z = 12 intersects paraboloid z = x^2 + y^2 in an ellipse.(a) Find the highest and the lowest points on the ell

emmasim [6.3K]

Answer:

a)

Highest (-3,-3)

Lowest (2,2)

b)

Farthest (-3,-3)

Closest (2,2)

Step-by-step explanation:

To solve this problem we will be using Lagrange multipliers.

a)

Let us find out first the restriction, which is the projection of the intersection on the XY-plane.

From x+y+z=12 we get z=12-x-y and replace this in the equation of the paraboloid:

$\bf 12-x-y=x^2+y^2\Rightarrow x^2+y^2+x+y=12$

completing the squares:

$\bf x^2+y^2+x+y=12\Rightarrow (x+1/2)^2-1/4+(y+1/2)^2-1/4=12\Rightarrow\\\\\Rightarrow (x+1/2)^2+(y+1/2)^2=12+1/2\Rightarrow (x+1/2)^2+(y+1/2)^2=25/2$

and we want the maximum and minimum of the paraboloid when (x,y) varies on the circumference we just found. That is, we want the maximum and minimum of

$\bf f(x,y)=x^2+y^2$

subject to the constraint

$\bf g(x,y)=(x+1/2)^2+(y+1/2)^2-25/2=0$

Now we have

$\bf \nabla f=(\displaystyle\frac{\partial f}{\partial x},\displaystyle\frac{\partial f}{\partial y})=(2x,2y)\\\\\nabla g=(\displaystyle\frac{\partial g}{\partial x},\displaystyle\frac{\partial g}{\partial y})=(2x+1,2y+1)$

Let $\bf \lambda$ be the Lagrange multiplier.

The maximum and minimum must occur at points where

$\bf \nabla f=\lambda\nabla g$

that is,

$\bf (2x,2y)=\lambda(2x+1,2y+1)\Rightarrow 2x=\lambda (2x+1)\;,2y=\lambda (2y+1)$

we can assume (x,y)≠ (-1/2, -1/2) since that point is not in the restriction, so

$\bf \lambda=\displaystyle\frac{2x}{(2x+1)} \;,\lambda=\displaystyle\frac{2y}{(2y+1)}\Rightarrow \displaystyle\frac{2x}{(2x+1)}=\displaystyle\frac{2y}{(2y+1)}\Rightarrow\\\\\Rightarrow 2x(2y+1)=2y(2x+1)\Rightarrow 4xy+2x=4xy+2y\Rightarrow\\\\\Rightarrow x=y$

Replacing in the constraint

$\bf (x+1/2)^2+(x+1/2)^2-25/2=0\Rightarrow (x+1/2)^2=25/4\Rightarrow\\\\\Rightarrow |x+1/2|=5/2$

from this we get

x=-1/2 + 5/2 = 2 or x = -1/2 - 5/2 = -3

and the candidates for maximum and minimum are (2,2) and (-3,-3).

Replacing these values in f, we see that

f(-3,-3) = 9+9 = 18 is the maximum and

f(2,2) = 4+4 = 8 is the minimum

b)

Since the square of the distance from any given point (x,y) on the paraboloid to (0,0) is f(x,y) itself, the maximum and minimum of the distance are reached at the points we just found.

We have then,

(-3,-3) is the farthest from the origin

(2,2) is the closest to the origin.

3 0

3 years ago

A researcher wants to test whether a certain sound will make rats do worse on learning tasks. It is known that an ordinary rat c

AveGali [126]

Answer:

So we reject the null hypothesis and accept the alternate hypothesis that rats learn slower with sound.

Step-by-step explanation:

In this data we have

Mean= u = 18

X= 38

Standard deviation = s= 6

1) We formulate the null and alternate hypothesis as

H0: u = 18 against Ha : u > 18 One tailed test .

2) The significance level alpha = ∝= 0.05 and Z alpha has a value ± 1.645 for one tailed test.

3)The test statistics used is

Z= X- u / s

z= 38-18/6= 3.333

4) The calculated value of z = 3.33 is greater than the z∝ = 1.645

5) So we reject the null hypothesis and accept the alternate hypothesis that rats learn slower with sound.

First we set the criteria for determining the true of value of the variable. That whether the rats learn in less or more than 18 trials.

Then we find the value of z for the given significance value given and the test about to be checked.

Then the test statistic is determined and calculated.

Then both value of z and z alpha re compared. If the test statistics falls in the rejection region reject the null hypothesis and conclude alternate hypothesis is true.

The figure shows that the calulated z value lies outside the given z values

4 0

2 years ago

1.8 = 2.1h - 5.7 - 4.6h h= __

Blababa [14]

Answer:

how are you doing

Step-by-step explanation:

7 0

2 years ago

Estimate the difference of the decimals below by rounding to the nearest whole number 42.706 - 4.423= ?