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1 year ago

What is the circumference of a circle with the radius of 9 inches?

Mathematics

1 answer:

Ksenya-84 [330]1 year ago

3 0

Answer:

If it is using pi as 3.14, it is 56.52.

If it is just the pi symbol, it is 18π.

Step-by-step explanation:

We do 9 x 3.14 = 28.26 and then you multiply that by 2 to get 56.52.

We do 9 x π = 9π. Then multiply by 2 to get 18π.

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Find the solution of the initial value problem<br><br> dy/dx=(-2x+y)^2-7 ,y(0)=0

Leokris [45]

Substitute $v(x)=-2x+y(x)$ , so that $\dfrac{\mathrm dv}{\mathrm dx}=-2+\dfrac{\mathrm dy}{\mathrm dx}$ . Then the ODE is equivalent to

$\dfrac{\mathrm dv}{\mathrm dx}+2=v^2-7$

which is separable as

$\dfrac{\mathrm dv}{v^2-9}=\mathrm dx$

Split the left side into partial fractions,

$\dfrac1{v^2-9}=\dfrac16\left(\dfrac1{v-3}-\dfrac1{v+3}\right)$

so that integrating both sides is trivial and we get

$\dfrac{\ln|v-3|-\ln|v+3|}6=x+C$

$\ln\left|\dfrac{v-3}{v+3}\right|=6x+C$

$\dfrac{v-3}{v+3}=Ce^{6x}$

$\dfrac{v+3-6}{v+3}=1-\dfrac6{v+3}=Ce^{6x}$

$\dfrac6{v+3}=1-Ce^{6x}$

$v=\dfrac6{1-Ce^{6x}}-3$

$-2x+y=\dfrac6{1-Ce^{6x}}-3$

$y=2x+\dfrac6{1-Ce^{6x}}-3$

Given the initial condition $y(0)=0$ , we find

$0=\dfrac6{1-C}-3\implies C=-1$

so that the ODE has the particular solution,

$\boxed{y=2x+\dfrac6{1+e^{6x}}-3}$

5 0

2 years ago

3x+1 = y 2x+3y = 14<br> please explain the steps if you can as well

Likurg_2 [28]

3x + 1 = y
2x + 3y = 14

To solve this system of equations, we are going to use the substitution method. Substitution the equation where the variable is isolated into the second equation. In this system of equations, y is isolated, so we will replace y in the second equation with 3x + 1.

2x + 3y = 14
2x + 3(3x + 1) = 14
2x + 9x + 3 = 14
We will add the like terms and subtract 3 from both sides of the equation.
11x + 3 = 14
11x = 11
x = 1
In this system of equations, x is equal to 1. Now we will go back and solve for y, plugging in 1 for x.
3(1) + 1 = y
2(1) + 3y = 14

3 + 1 = y
2 + 3y = 14

4 = y
3y = 2

4 = y
4 = y

The solution to this system of equations is (1, 4).

8 0

2 years ago

The edge of the square is 33 cm.

Aleks [24]

Answer:

46.6

Step-by-step explanation:

${x}^{2} = {33}^{2} + {33}^{2} \\ x = \sqrt{2178} \\ x = 46.6 \: cm$