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2 years ago

Grade 6 please answer this

Mathematics

1 answer:

Scrat [10]2 years ago

6 0

Answer:

Step-by-step explanation:

follow PEMDAS (parentheses, exponent, multiplication, division, addition, subtraction)

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Find the arc-length parametrization of the curve that is the intersection of the elliptic cylinder x 2 + y 2/2 = 1 and the plane

storchak [24]

Answer:

$f(\theta) = (cos(\frac{\theta}{\sqrt2}), \sqrt2 sin(\frac{\theta}{\sqrt2}), cos(\frac{\theta}{\sqrt2})-2)$

0 ≤ Ф ≤ 4π.

Step-by-step explanation:

since x²+y²/2 = 1, then x²+s² = 1, with s = (y/√2)². Hence, (x,s) = (cos(Ф),sin(Ф)) and (x,y,z) = (cos(Ф),√2 sin(Ф), cos(Ф)-2). This expression evaluated in zero gives as result (1,0,-1). The derivate of this function is (-sin(Ф),√2 cos(Ф), -sen(Ф))

the norm of the derivate is √(sin²(Ф) + 2cos²(Ф)+sin²(Ф)) = √2. In order to make the norm equal to 1, i will divide Ф by √2, so that a √2 is dividing each term after derivating.

We take

$f(\theta) = (cos(\frac{\theta}{\sqrt2}), \sqrt2 sin(\frac{\theta}{\sqrt2}), cos(\frac{\theta}{\sqrt2})-2)$

Note that

$f(0) = (1,0,-1)$
$f'(\theta) = (\frac{sin(\frac{\theta}{\sqrt2})}{\sqrt2}, cos(\frac{\theta}{\sqrt2})}, \frac{sin(\frac{\theta}{\sqrt2})}{\sqrt2})$

Whose square norm is 1/2cos²(Ф/2)+sen²(Ф/2)+1/2cos²(Ф/2) = 1. This is te parametrization that we wanted.

The values from Ф range between 0 an 4π, because the argument of the sin and cos is Ф/2, not Ф, Ф/2 should range between 0 and 2π.

6 0

3 years ago

Sa se gaseasca numerele a si b a caror medie aritmetica este 200 si care sunt invers proportionale cu 8 si respectiv 4,5.

Olenka [21]

Bonjour, (as you write in roumain)

Soient a et b les 2 nombres

(a+b)/2=200==>a+b=400

8/a=4.5/b==>16b=9a

a+9a/16=400
==> 25a/16=400
==>a=400*16/25
==>a=256
et b= 9*256/16; b=144

3 0

3 years ago

A woman in a highland village in the Andes knits sweaters and sells them for export. She also takes care of her family and helps

Mnenie [13.5K]

Answer:

Expected number of sweaters per month can be given as follows:

E(X) = Σ x P(X = x)

Now,

E(X) = [2 * 0.1 + 3* 0.1+ 4* 0.2 + 5* 0.3 + 6* 0.2 + 7 * 0.1]

E(X) = 4.7.

Var(X) = E(X^2) – [E(X)]^2

We have E(X) = 4.7. Thus, [E(X)]2= 4.7*4.7 = 22.09.

Now E(X^2) = [2*2 * 0.1 + 3*3* 0.1+ 4*4* 0.2 + 5*5* 0.3 + 6*6* 0.2 + 7*7*0.1]

E(X^2) = 24.1

Thus by formula, Var(X) = E(X2) – [E(X)]2

Var(X) = 24.1-22.09

Var(X) = 2.01

Given that exporter pays the $12 for each sweater. The woman pays $2 per sweater. The cost of shipment is $3 irrespective of the number of sweaters. Now, let m is the number of sweaters she made. Thus, the total cost she would have to pay would be

Total cost by woman = 2m+3

The total cost paid by the exporter would be = 12m.

Now the profit of woman would be given by,

= The total cost exporter pay – cost paid by the woman

= 12m – (2m +3)

= 12m – 2m -3

= 10m – 3.

Now expected profit made by the woman is given in the following table below:

E(Profit) = Σ profit* P(X = x)

In a similar way, as we have done in part (a).

E(Profit) = [17 * 0.1 + 27* 0.1+ 37* 0.2 + 47* 0.3 + 57* 0.2 + 67 * 0.1]

E(Profit) = 44.

Now, we calculate the variance:

Var(profit) = E(profit^2) – [E(profit)]^2

Var(profit) =

E(profit^2) = [17*17 * 0.1 + 27*27* 0.1+ 37*37* 0.2 + 47*47* 0.3 + 57*57* 0.2 + 67*67*0.1]

E(profit^2) = 2137.

[E(profit)]^2 = 44*44 = 1936.

Thus, the variance can be given as =

Var(profit)= 2137 – 1936

Var(profit) = 201.

6 0

2 years ago

How to solve. 0.05x+0.02x=4.9

vitfil [10]

<span>0.07x = 4.9 I hope this helps (;</span>

3 0

3 years ago

Read 2 more answers

Which expression gives the x-coordinate of the solution of the system?

aalyn [17]

To find the the expression that gives the value of $x$ we are going to proceed as follows:
$5x+3y=-18$ equation (1)
$2x-4y=-28$ equation (1)

Step 1. solve for $y$ in equation (2)
$2x-4y=-28$
$-4y=-28-2x$
$y= \frac{-28-2x}{-4}$
$y=7+ \frac{1}{2} x$ equation (3)

Step 3. Replace equation (3) in equation (1) and solve for $x$
$5x+3y=-18$
$5x+3(7+ \frac{1}{2} x)=-18$
$5x+21+ \frac{3}{2} x=-18$
$\frac{13}{2} x=-39$
$x= \frac{-39(2)}{(13)}$
$x=-6$

We can conclude that the expression that gives the value of $x$ is: $x=-6$

7 0

3 years ago