4x^2+4x+1=9 what are all the solutions? Thanks

stellarik [79]

The volume would be, 24.
:)

7 0

3 years ago

A 1000-liter (L) tank contains 500 L of water with a salt concentration of 10 g/L. Water with a salt concentration of 50 g/L flo

djverab [1.8K]

Answer:

a) $y(t)=50000-49990e^{\frac{-2t}{25}}$

b) $31690.7 g/L$

Step-by-step explanation:

By definition, we have that the change rate of salt in the tank is $\frac{dy}{dt}=R_{i}-R_{o}$ , where $R_{i}$ is the rate of salt entering and $R_{o}$ is the rate of salt going outside.

Then we have, $R_{i}=80\frac{L}{min}*50\frac{g}{L}=4000\frac{g}{min}$ , and

$R_{o}=40\frac{L}{min}*\frac{y}{500} \frac{g}{L}=\frac{2y}{25}\frac{g}{min}$

So we obtain. $\frac{dy}{dt}=4000-\frac{2y}{25}$ , then

$\frac{dy}{dt}+\frac{2y}{25}=4000$ , and using the integrating factor $e^{\int {\frac{2}{25}} \, dt=e^{\frac{2t}{25}$ , therefore $(\frac{dy }{dt}+\frac{2y}{25}}=4000)e^{\frac{2t}{25}$ , we get $\frac{d}{dt}(y*e^{\frac{2t}{25}})= 4000 e^{\frac{2t}{25}$ , after integrating both sides $y*e^{\frac{2t}{25}}= 50000 e^{\frac{2t}{25}}+C$ , therefore $y(t)= 50000 +Ce^{\frac{-2t}{25}}$ , to find $C$ we know that the tank initially contains a salt concentration of 10 g/L, that means the initial conditions $y(0)=10$ , so $10= 50000+Ce^{\frac{-0*2}{25}}$

$10=50000+C\\C=10-50000=-49990$

Finally we can write an expression for the amount of salt in the tank at any time t, it is $y(t)=50000-49990e^{\frac{-2t}{25}}$

b) The tank will overflow due Rin>Rout, at a rate of $80 L/min-40L/min=40L/min$ , due we have 500 L to overflow $\frac{500L}{40L/min} =\frac{25}{2} min=t$ , so we can evualuate the expression of a) $y(25/2)=50000-49990e^{\frac{-2}{25}\frac{25}{2}}=50000-49990e^{-1}=31690.7$ , is the salt concentration when the tank overflows

4 0

3 years ago

Which vector matrix represents the reflection of the vector <-1,5> across the line x = y

Arturiano [62]

Answer:

$V = \left[\begin{array}{ccc}5&-1\end{array}\right]$

Step-by-step explanation:

We want to reflect this 2x1 vector on the line y = x.

To make this reflection we must use the following matrix:

$R=\left[\begin{array}{cc}0&1\\1&0\\\end{array}\right]$

Where R is known as the reflection matrix on the line x = y

Now perform the product of the vector <-1,5> x R.

$\left[\begin{array}{ccc}-1\\5\end{array}\right]x\left[\begin{array}{ccc}0&1\\1&0\end{array}\right]\\\\\\\left[\begin{array}{ccc}-1(0) +5(1)&-1(1)+5(0)\end{array}\right]\\\\\\\left[\begin{array}{ccc}5&-1\end{array}\right]$

The vector matrix that represents the reflection of the vector <-1,5> across the line x = y is:

$V = \left[\begin{array}{ccc}5&-1\end{array}\right]$

6 0

3 years ago

HELPP please.. please pleaae

Zinaida [17]

Answer:

A=80

B=31

C=64

Step-by-step explanation:

A, 69, and b will equal 180 since it forms a straight line

A+69+b=180

to solve for A we subtract 53+47 from 180 and get 80

80+69+b=180

to get B we subtract 80+69 from 180 and get 31

to get c we add 85+b and subtract it from 180 getting c=64

6 0

3 years ago

Read 2 more answers

Help PLEASE ive been stuck on this forever!

AlekseyPX

Answer:

1/5

Step-by-step explanation:

2/10=1/5

4 0

3 years ago