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2 years ago

Estimate the sum of 1,256, 379 and 305,986 by first rounding each number to the nearest ten thousand.

Mathematics

1 answer:

KatRina [158]2 years ago

3 0

9514 1404 393

Answer:

1,570,000

Step-by-step explanation:

The sum is approximately ...

1,260,000 +310,000 = 1,570,000

_____

<em>Additional comment</em>

It is a good idea to estimate the error associated with an estimate. Here, both numbers are rounded up by about 4000 each, so the estimate is around 8000 high.

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A particle moving in a planar force field has a position vector x that satisfies x'=Ax. The 2×2 matrix A has eigenvalues 4 and 2

andrey2020 [161]

Answer:

The required position of the particle at time t is: $x(t)=\begin{bmatrix}-7.5e^{4t}+1.5e^{2t}\\2.5e^{4t}-1.5e^{2t}\end{bmatrix}$

Step-by-step explanation:

Consider the provided matrix.

$v_1=\begin{bmatrix}-3\\1 \end{bmatrix}$

$v_2=\begin{bmatrix}-1\\1 \end{bmatrix}$

$\lambda_1=4, \lambda_2=2$

The general solution of the equation $x'=Ax$

$x(t)=c_1v_1e^{\lambda_1t}+c_2v_2e^{\lambda_2t}$

Substitute the respective values we get:

$x(t)=c_1\begin{bmatrix}-3\\1 \end{bmatrix}e^{4t}+c_2\begin{bmatrix}-1\\1 \end{bmatrix}e^{2t}$

$x(t)=\begin{bmatrix}-3c_1e^{4t}-c_2e^{2t}\\c_1e^{4t}+c_2e^{2t} \end{bmatrix}$

Substitute initial condition $x(0)=\begin{bmatrix}-6\\1 \end{bmatrix}$

$\begin{bmatrix}-3c_1-c_2\\c_1+c_2 \end{bmatrix}=\begin{bmatrix}-6\\1 \end{bmatrix}$

Reduce matrix to reduced row echelon form.

$\begin{bmatrix} 1& 0 & \frac{5}{2}\\ 0& 1 & \frac{-3}{2}\end{bmatrix}$

Therefore, $c_1=2.5,c_2=1.5$

Thus, the general solution of the equation $x'=Ax$

$x(t)=2.5\begin{bmatrix}-3\\1\end{bmatrix}e^{4t}-1.5\begin{bmatrix}-1\\1 \end{bmatrix}e^{2t}$

$x(t)=\begin{bmatrix}-7.5e^{4t}+1.5e^{2t}\\2.5e^{4t}-1.5e^{2t}\end{bmatrix}$

The required position of the particle at time t is: $x(t)=\begin{bmatrix}-7.5e^{4t}+1.5e^{2t}\\2.5e^{4t}-1.5e^{2t}\end{bmatrix}$

6 0

3 years ago

What is the substitution for 3x+4y^2 if x= -2 and y=3?

solniwko [45]

Answer:

Step-by-step explanation:

$3x+4y^2\\\\\text{Substitute the value of x = -2 and y = 3 to the expression:}\\\\3(-2)+4(3^2)\qquad\text{use PEMDAS}\\\\=-6+4(9)=-6+36=30$

5 0

3 years ago

2.1 in a decimal form

Allisa [31]

2.1 is already in a decimal form.

Hope I helped!

7 0

3 years ago

4 x equals negative 2x + negative 6

erastovalidia [21]

So x equals two if it is an exponent.9

7 0

3 years ago

Read 2 more answers

Roberto must make his costume for his school play. He needs a piece of fabric that is 2 2/3 yards long and 1 1/2 yards wide. Wha

erik [133]

Answer:

He will need 8.34 yards of fabric.

Step-by-step explanation:

Given that,

The length of the fabric, l = 2 2/3 yards = 8/3 yards

The width of the fabric, b = 1 1/2 yards = 3/2 yards

We need to find the piece of fabric Roberto needs. It is equal to the perimeter of the fabric such that,

$P=2(l+b)\\\\P=2(\dfrac{8}{3}+\dfrac{3}{2})\\\\P=2\times \dfrac{25}{6}\\\\P=8.34\ \text{yards}$

So, he will need 8.34 yards of fabric.

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3 years ago