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1 year ago

14

a garrison of 60 soldiers had provisions for 45 days. if 15 more soldiers joined the garrison, for how long would the same provi

sion last?

1 answer:

Eva8 [605]1 year ago

5 0

Answer:

36 days.

Step-by-step explanation:

60 + 15 = 75 soldiers.

By proportion the number of days that the provisions will last

= 45 * (60/75)

= 45 * 4/5

= 36 days.

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8 multiplied by the sum of a number and 5 is 24.

ziro4ka [17]

Answer:

-2

Step-by-step explanation:

24/8 (Opposite of multiplied)

=3

-5 (The opposite of sum)

3-5

-2

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2 years ago

4. Which property of operations is used to write 15x + 9 as 9 + 15x?

suter [353]

Solution: The commutative property of addition states that when two numbers are being added, their order can be changed without affecting the sum.

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2 years ago

Solve r = 1/2m^2p for p

hoa [83]

You just have to arrange the equation such that the p is the only term at the left hand side of the equation. Express it in terms of r and m.

r = 1/2*m²*p
Divide both left and right hand side equations by 1/2*m²
p = r/(1/2 *m²)
Take the reciprocal of 1/2 and multiply it. The final answer is:
p = 2r/m²

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3 years ago

For each of the following vector fields F , decide whether it is conservative or not by computing curl F . Type in a potential f

Phantasy [73]

The key idea is that, if a vector field is conservative, then it has curl 0. Equivalently, if the curl is not 0, then the field is not conservative. But if we find that the curl is 0, that on its own doesn't mean the field is conservative.

1.

$\mathrm{curl}\vec F=\dfrac{\partial(5x+10y)}{\partial x}-\dfrac{\partial(-6x+5y)}{\partial y}=5-5=0$

We want to find $f$ such that $\nabla f=\vec F$ . This means

$\dfrac{\partial f}{\partial x}=-6x+5y\implies f(x,y)=-3x^2+5xy+g(y)$

$\dfrac{\partial f}{\partial y}=5x+10y=5x+\dfrac{\mathrm dg}{\mathrm dy}\implies\dfrac{\mathrm dg}{\mathrm dy}=10y\implies g(y)=5y^2+C$

$\implies\boxed{f(x,y)=-3x^2+5xy+5y^2+C}$

so $\vec F$ is conservative.

2.

$\mathrm{curl}\vec F=\left(\dfrac{\partial(-2y)}{\partial z}-\dfrac{\partial(1)}{\partial y}\right)\vec\imath+\left(\dfrac{\partial(-3x)}{\partial z}-\dfrac{\partial(1)}{\partial z}\right)\vec\jmath+\left(\dfrac{\partial(-2y)}{\partial x}-\dfrac{\partial(-3x)}{\partial y}\right)\vec k=\vec0$

Then

$\dfrac{\partial f}{\partial x}=-3x\implies f(x,y,z)=-\dfrac32x^2+g(y,z)$

$\dfrac{\partial f}{\partial y}=-2y=\dfrac{\partial g}{\partial y}\implies g(y,z)=-y^2+h(y)$

$\dfrac{\partial f}{\partial z}=1=\dfrac{\mathrm dh}{\mathrm dz}\implies h(z)=z+C$

$\implies\boxed{f(x,y,z)=-\dfrac32x^2-y^2+z+C}$

so $\vec F$ is conservative.

3.

$\mathrm{curl}\vec F=\dfrac{\partial(10y-3x\cos y)}{\partial x}-\dfrac{\partial(-\sin y)}{\partial y}=-3\cos y+\cos y=-2\cos y\neq0$

so $\vec F$ is not conservative.

4.

$\mathrm{curl}\vec F=\left(\dfrac{\partial(5y^2)}{\partial z}-\dfrac{\partial(5z^2)}{\partial y}\right)\vec\imath+\left(\dfrac{\partial(-3x^2)}{\partial z}-\dfrac{\partial(5z^2)}{\partial x}\right)\vec\jmath+\left(\dfrac{\partial(5y^2)}{\partial x}-\dfrac{\partial(-3x^2)}{\partial y}\right)\vec k=\vec0$

Then

$\dfrac{\partial f}{\partial x}=-3x^2\implies f(x,y,z)=-x^3+g(y,z)$

$\dfrac{\partial f}{\partial y}=5y^2=\dfrac{\partial g}{\partial y}\implies g(y,z)=\dfrac53y^3+h(z)$

$\dfrac{\partial f}{\partial z}=5z^2=\dfrac{\mathrm dh}{\mathrm dz}\implies h(z)=\dfrac53z^3+C$

$\implies\boxed{f(x,y,z)=-x^3+\dfrac53y^3+\dfrac53z^3+C}$

so $\vec F$ is conservative.

4 0

3 years ago

Find the slope and y-intercept of the line 6x−7y=2

Allisa [31]

To easily find the slope and y intercept of the line, put it in slope intercept form by rearranging the variables around.

6x-7y = 2
6x - 7y + 7y = 2 + 7y
6x = 7y + 2
6x - 2 = 7y + 2 - 2
7y = 6x - 2
7y/7 = 6x/7 - 2/7
Y = 6/7(X) - 2/7

Y = 6/7x - 2/7
Slope = m = 6/7
Y intercept = b = -2/7
(0, -2/7).

3 0

2 years ago