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3 years ago

A rectangular wall measures 1620cm by 68cm. Estimate the area of the wall.

Mathematics

1 answer:

mixer [17]3 years ago

5 0

Length×width≈area
1620×68≈110160cm²

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Solve: 2x+3y=1 y=-2x+11

Sauron [17]

Answer:

(8, -5); x=8; y=-5

Step-by-step explanation:

i'll be solving via substitution

2x+3y=1; y=-2x+11

2x + 3(-2x +11) = 1

2x -6x +33 = 1

-4x = -32

x = 8

2(8) + 3y = 1

16 + 3y = 1

3y = -15

y = -5

(8, -5)

Check:

-5 = -2(8) + 11

-5 = -16 + 11

-5 = -5

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3 years ago

Find the missing angle measurements. Screenshot included.

zheka24 [161]

One of the missing angles is 45degrees 64+71=135 then subtract from 180 since it is a triangle. Then 64 are vertical angles with the one across from it which stays the same. The last angle would be 64+56=120 and 180-120=60 which would be the last angle. Hope this Helps... Juan

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3 years ago

Daniel wants to create a banner for his construction business to hang at the house he just built. Daniel will use a single sign

Nina [5.8K]

The solution for this problem is just simple. It tells you to find the area in square feet. Thus, convert the units to feet first. The conversion you need to know are: 12 in = 1 ft and 3 ft = 1 yard.

Width = 42 in * 1 ft/12 in = 3.5 ft
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Area = Length*Width = 30*3.5
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3 0

3 years ago

Let y(t) be the solution to y˙=3te−y satisfying y(0)=3 . (a) Use Euler's Method with time step h=0.2 to approximate y(0.2),y(0.4

OLEGan [10]

Answer:

$y(0.2)=3$ , $y(0.4)=3.005974448$ , $y(0.6)=3.017852169$ , $y(0.8)=3.035458382$ , and $y(1.0)=3.058523645$

The general solution is $y=\ln \left(\frac{3t^2}{2}+e^3\right)$

The error in the approximations to y(0.2), y(0.6), and y(1):

$|y(0.2)-y_{1}|=0.002982771$

$|y(0.6)-y_{3}|=0.008677796$

$|y(1)-y_{5}|=0.013499859$

Step-by-step explanation:

Point a:

The Euler's method states that:

$y_{n+1}=y_n+h \cdot f \left(t_n, y_n \right)$ where $t_{n+1}=t_n + h$

We have that $h=0.2$ , $t_{0}=0$ , $y_{0} =3$ , $f(t,y)=3te^{-y}$

We need to find $y(0.2)$ for $y'=3te^{-y}$ , when $y(0)=3$ , $h=0.2$ using the Euler's method.

So you need to:

$t_{1}=t_{0}+h=0+0.2=0.2$

$y\left(t_{1}\right)=y\left(0.2)=y_{1}=y_{0}+h \cdot f \left(t_{0}, y_{0} \right)=3+h \cdot f \left(0, 3 \right)=$

$=3 + 0.2 \cdot \left(0 \right)= 3$

$y(0.2)=3$

We need to find $y(0.4)$ for $y'=3te^{-y}$ , when $y(0)=3$ , $h=0.2$ using the Euler's method.

So you need to:

$t_{2}=t_{1}+h=0.2+0.2=0.4$

$y\left(t_{2}\right)=y\left(0.4)=y_{2}=y_{1}+h \cdot f \left(t_{1}, y_{1} \right)=3+h \cdot f \left(0.2, 3 \right)=$

$=3 + 0.2 \cdot \left(0.02987224102)= 3.005974448$

$y(0.4)=3.005974448$

The Euler's Method is detailed in the following table.

Point b:

To find the general solution of $y'=3te^{-y}$ you need to:

Rewrite in the form of a first order separable ODE:

$e^yy'\:=3t\\e^y\cdot \frac{dy}{dt} =3t\\e^y \:dy\:=3t\:dt$

Integrate each side:

$\int \:e^ydy=e^y+C$

$\int \:3t\:dt=\frac{3t^2}{2}+C$

$e^y+C=\frac{3t^2}{2}+C\\e^y=\frac{3t^2}{2}+C_{1}$

We know the initial condition y(0) = 3, we are going to use it to find the value of $C_{1}$

$e^3=\frac{3\left(0\right)^2}{2}+C_1\\C_1=e^3$

So we have:

$e^y=\frac{3t^2}{2}+e^3$

Solving for y we get:

$\ln \left(e^y\right)=\ln \left(\frac{3t^2}{2}+e^3\right)\\y\ln \left(e\right)=\ln \left(\frac{3t^2}{2}+e^3\right)\\y=\ln \left(\frac{3t^2}{2}+e^3\right)$