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3 years ago

What is the answer and how do you even do this please help

Mathematics

1 answer:

Degger [83]3 years ago

7 0

Answer:

Where is the question or problem that you want answered?

Step-by-step explanation:

I won't be of much help if I do not know what is it that you are asking help for.

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What is the volume of a pyramid that is 11 inches tall and has a base of 4 inches

Elina [12.6K]

The volume is 58.67

I used the the formula V= l*w*h / 3 to solve for the volune of a pyramid

6 0

3 years ago

Determine the values of the constants r and s such that i(x, y) = x rys is an integrating factor for the given differential equa

garri49 [273]

$\underbrace{y(7xy^2+6)}_{M(x,y)}\,\mathrm dx+\underbrace{x(xy^2-1)}_{N(x,y)}\,\mathrm dy=0$

For the ODE to be exact, we require that $M_y=N_x$ , which we'll verify is not the case here.

$M_y=21xy^2+6$
$N_x=2xy^2-1$

So we distribute an integrating factor $i(x,y)$ across both sides of the ODE to get

$iM\,\mathrm dx+iN\,\mathrm dy=0$

Now for the ODE to be exact, we require $(iM)_y=(iN)_x$ , which in turn means

$i_yM+iM_y=i_xN+iN_x\implies i(M_y-N_x)=i_xN-i_yM$

Suppose $i(x,y)=x^ry^s$ . Then substituting everything into the PDE above, we have

$x^ry^s(19xy^2+7)=rx^{r-1}y^s(x^2y^2-x)-sx^ry^{s-1}(7xy^3+6y)$
$19x^{r+1}y^{s+2}+7x^ry^s=rx^{r+1}y^{s+2}-rx^ry^s-7sx^{r+1}y^{s+2}-6sx^ry^s$
$19x^{r+1}y^{s+2}+7x^ry^s=(r-7s)x^{r+1}y^{s+2}-(r+6s)x^ry^s$
$\implies\begin{cases}r-7s=19\\r+6s=-7\end{cases}\implies r=5,s=-2$

so that our integrating factor is $i(x,y)=x^5y^{-2}$ . Our ODE is now

$(7x^6y+6x^5y^{-1})\,\mathrm dx+(x^7-x^6y^{-2})\,\mathrm dy=0$

Renaming $M(x,y)$ and $N(x,y)$ to our current coefficients, we end up with partial derivatives

$M_y=7x^6-6x^5y^{-2}$
$N_x=7x^6-6x^5y^{-2}$

as desired, so our new ODE is indeed exact.

Next, we're looking for a solution of the form $\Psi(x,y)=C$ . By the chain rule, we have

$\Psi_x=7x^6y+6x^5y^{-1}\implies\Psi=x^7y+x^6y^{-1}+f(y)$

Differentiating with respect to $y$ yields

$\Psi_y=x^7-x^6y^{-2}=x^7-x^6y^{-2}+\dfrac{\mathrm df}{\mathrm dy}$
$\implies\dfrac{\mathrm df}{\mathrm dy}=0\implies f(y)=C$

Thus the solution to the ODE is

$\Psi(x,y)=x^7y+x^6y^{-1}=C$

4 0

3 years ago

What’s the constant term and 4th and 5th term?

yulyashka [42]

Answer:a constant term is a term in an algebraic expression that has a value that is [constant function|constant]] or cannot change

Step-by-step explanation:

4 0

2 years ago

Yuki works at a garden store. She is stacking 40-pound bags of soil. Use the equation w=40b to find the total weight, w, of 5 ba

NeTakaya

Answer:

w= 40b

w=40× 5

w=200

......

4 0

3 years ago

Please help me! i got this wrong and i dont know what i did wrong

Genrish500 [490]

Answer: See you have to understand the problem and then solve it Answer is: 5g - 2/10

8 0

3 years ago

What is the answer and how do you even do this please help​

What is the answer and how do you even do this please help