All categories

3 years ago

What is the formula for area of a circle? 100 points

Mathematics

2 answers:

wel3 years ago

6 0

Hello!

The formula for the area of a circle is:

A = $\pi$ x r²

sergiy2304 [10]3 years ago

3 0

Area = π r^2 where r = radius of the circle.

You might be interested in

Which graph represents the hyperbola of (x ^ 2)/9 + (y ^ 2)/4 = 1

Lerok [7]

Answer:

Ellipse

Step-by-step explanation:

(x ^ 2)/9 + (y ^ 2)/4 = 1

x^2/a^2+y^2/b^2=1

5 0

3 years ago

PLLSSS REALLY URGENT <br> If g(x)=3x+4, determine n that g(-3)=g^-1(n).

grigory [225]

Answer:

we have:

g(-3) = 3.(-3) + 4 = -5

$g {}^{ - 1} (n) = \frac{1}{3n + 4}$

because

$g( - 3) = g {}^{ - 1} (n)$

$- 5 = \frac{1}{3n + 4} \\ \\ < = > - 5(3n + 4) = 1 \\ \\ < = > - 15n - 20 = 1 \\ \\ < = > n = \frac{ - 21}{15} \\ \\ < = > n = \frac{ - 7}{5}$

5 0

3 years ago

Use the method of undetermined coefficients to find the general solution to the de y′′−3y′ 2y=ex e2x e−x

djverab [1.8K]

I'll assume the ODE is

$y'' - 3y' + 2y = e^x + e^{2x} + e^{-x}$

Solve the homogeneous ODE,

$y'' - 3y' + 2y = 0$

The characteristic equation

$r^2 - 3r + 2 = (r - 1) (r - 2) = 0$

has roots at $r=1$ and $r=2$ . Then the characteristic solution is

$y = C_1 e^x + C_2 e^{2x}$

For nonhomogeneous ODE (1),

$y'' - 3y' + 2y = e^x$

consider the ansatz particular solution

$y = axe^x \implies y' = a(x+1) e^x \implies y'' = a(x+2) e^x$

Substituting this into (1) gives

$a(x+2) e^x - 3 a (x+1) e^x + 2ax e^x = e^x \implies a = -1$

For the nonhomogeneous ODE (2),

$y'' - 3y' + 2y = e^{2x}$

take the ansatz

$y = bxe^{2x} \implies y' = b(2x+1) e^{2x} \implies y'' = b(4x+4) e^{2x}$

Substitute (2) into the ODE to get

$b(4x+4) e^{2x} - 3b(2x+1)e^{2x} + 2bxe^{2x} = e^{2x} \implies b=1$

Lastly, for the nonhomogeneous ODE (3)

$y'' - 3y' + 2y = e^{-x}$

take the ansatz

$y = ce^{-x} \implies y' = -ce^{-x} \implies y'' = ce^{-x}$

and solve for $c$ .

$ce^{-x} + 3ce^{-x} + 2ce^{-x} = e^{-x} \implies c = \dfrac16$

Then the general solution to the ODE is

$\boxed{y = C_1 e^x + C_2 e^{2x} - xe^x + xe^{2x} + \dfrac16 e^{-x}}$

6 0

1 year ago

Solve the system using elimination

Pie

Answer:

(x, y) = (3, 1)

Step-by-step explanation:

given the 2 equations

2x + 3y = 9 → (1)

x + 5y = 8 → (2)

multiplying (2) by - 2 then adding to (1) will eliminate the term in x

multiply (2) by - 2

- 2x - 10y = - 16 → (3)

add 1(1) and (3) term by term

(2x - 2x) + (3y - 10y) = (9 - 16)

- 7y = - 7 ( divide both sides by - 7 )

y = 1

Substitute y = 1 in either (1) or (2) and solve for x

(1) : 2x + 3 = 9 ( subtract 3 from both sides )

2x = 6 ( divide both sides by 2 )

x = 3

Solution is (3, 1 )

5 0

3 years ago

Phoebe has 4 bags of cat food. She feeds her cat 1/5 of a bag

Annette [7]

Answer:

20 days

Step-by-step explanation:

5 days for each bag becuase each day is 1/5 5 days=5/5 (1 whole).

there are 4 bag so we do 5*4=20.

It would take 20 days to finsih all the bags.

PLEASE GIVE BRAINLIEST

6 0

2 years ago

Read 2 more answers