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2 years ago

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If the ratio of boys to girls is 1:4 and there are 20 girls in your class, how many boys are there?

2 answers:

Sonja [21]2 years ago

8 0

Answer:

Step-by-step explanation:

5 boys

Oxana [17]2 years ago

7 0

Answer:

me

Step-by-step explanation:

beceaus im the best Guy

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Consider the following differential equation to be solved by undetermined coefficients. y(4) − 2y''' + y'' = ex + 1 Write the gi

kompoz [17]

Answer:

The general solution is

$y= (C_{1}+C_{1}x) e^0x+(C_{3}+C_{4}x) e^x +\frac{1}{2} (e^x(x^2-2x+2)-e^x(2(x-1)+e^x(2))$

+ $\frac{x^2}{2}$

Step-by-step explanation:

Step :1:-

Given differential equation y(4) − 2y''' + y'' = e^x + 1

The differential operator form of the given differential equation

$(D^4 -2D^3+D^2)y = e^x+1$

comparing f(D)y = e^ x+1

The auxiliary equation (A.E) f(m) = 0

$m^4 -2m^3+m^2 = 0$

$m^2(m^2 -2m+1) = 0$

$(m^2 -2m+1) this is the expansion of (a-b)^2$

$m^2 =0 and (m-1)^2 =0$

The roots are m=0,0 and m =1,1

complementary function is $y_{c} = (C_{1}+C_{1}x) e^0x+(C_{3}+C_{4}x) e^x$

<u>Step 2</u>:-

The particular equation is $\frac{1}{f(D)} Q$

P.I = $\frac{1}{D^2(D-1)^2} e^x+1$

P.I = $\frac{1}{D^2(D-1)^2} e^x+\frac{1}{D^2(D-1)^2}e^{0x}$

P.I = $I_{1} +I_{2}$

$\frac{1}{D^2} (\frac{x^2}{2!} )e^x + \frac{1}{D^{2} } e^{0x}$

$\frac{1}{D} means integration$

$\frac{1}{D^2} (\frac{x^2}{2!} )e^x = \frac{1}{2D} \int\limits {x^2e^x} \, dx$

applying in integration u v formula

$\int\limits {uv} \, dx = u\int\limits {v} \, dx - \int\limits ({u^{l}\int\limits{v} \, dx } )\, dx$

$I_{1}$ = $\frac{1}{D^2(D-1)^2} e^x$

$\frac{1}{2D} (e^x(x^2)-e^x(2x)+e^x(2))$

$\frac{1}{2} (e^x(x^2-2x+2)-e^x(2(x-1)+e^x(2))$

$I_{2}$ $= \frac{1}{D^2(D-1)^2}e^{0x}$

$\frac{1}{D} \int\limits {1} \, dx= \frac{1}{D} x$

again integration $\frac{1}{D} x = \frac{x^2}{2!}$

The general solution is $y = y_{C} +y_{P}$

$y= (C_{1}+C_{1}x) e^0x+(C_{3}+C_{4}x) e^x +\frac{1}{2} (e^x(x^2-2x+2)-e^x(2(x-1)+e^x(2))$

+ $\frac{x^2}{2!}$

3 0

3 years ago

Given that the hypotenuse of a triangle is c, which is the Pythagorean Theorem? a2 + c2 = b2 a2 – b2 = c2 2a + 2b = 2c none of t

Alexandra [31]

The pythagorean theorem states that a^2+ b^2=c^2.
Final answer: None of the above

6 0

3 years ago

Read 2 more answers

What is the sum of (q+r)-(r+10)

KATRIN_1 [288]

Answer:

q+10 is the answer

6 0

3 years ago

A company wants to decrease their energy use by 10%. If their electric bill is currently $1,900 a month, what will their bill be

NemiM [27]

Answer:

A. $1,710

B. Yes, probably.

Step-by-step explanation:

Assuming that a 10% decrease in energy use leads to a 10% decrease in the electric bill:

We'll want to find the value which is 10% less than the original value, i.e., the bill cost which is 90% of the original bill.

90% = 0.9

Since the original bill was $1900, we can just multiply 1900 by 0.9:

$1900*0.9=1710$

Answer: A bill of $1,710 would equal a 10% decrease.

Since $1,672 is less than that, then they have decreased their energy use by more than 10% which is likely a success.

Answer: Yes, probably.

5 0

3 years ago

Line segment AB has endpoints A(-1.5, 0) and B(4.5 8). Point C is on line segment AB located at (0, 2)

Pie

Answer:

The ratio of AC/CB=1/3

Step-by-step explanation:

We use the section formula:

$(\frac{mx_2+nx_1}{m+n},\frac{my_2+ny_1}{m+n})$

We substitute the point A(-1.5,0) and B(4.5,8).

We plug in the points to get:

$(\frac{4.5m - 1.5n}{m+n},\frac{8m+n \times 0}{m+n})$

This is supposed to be equal to: (0,2).

$(\frac{4.5m - 1.5n}{m+n},\frac{8m+n \times 0}{m+n}) = (0,2)$

We can equate, corresponding coordinates to find m and n.

$\frac{4.5m - 1.5n}{m + n} = 0$

This implies that:

$4.5m - 1.5n = 0$

$4.5m = 1.5n$

$\frac{m}{n} = \frac{1.5}{4.5}$

$\frac{m}{n} = \frac{1}{3}$

Therefore the ratio is m:n=1:3

4 0

3 years ago