Help please.. DuE Today. No LiNkS!! Thanks! 8th Grade Mathh No.2

In a circle, area and circumference can be found using the formulas A=(pi)r^2 and C=2(pi)r, respectively, Write a formula for A

AURORKA [14]

Answer:

$A = \dfrac{C^2}{4\pi}$

Step-by-step explanation:

Given that

Area of a circle $A=\pi r^2$

Circumference of the circle $C = 2 \pi r$

Let us re-write the equation of area of circle:

$A=\pi r^2$

$A = \pi \times r \times r$

Multiplying and dividing with 2:

$A = \dfrac{2\pi r}{2} \times r\\\text{Putting }2\pi r = C:\\\Rightarrow A = \dfrac{C}{2} \times r\\\text{Multiplying and dividing by } 2\pi:\\\Rightarrow A = \dfrac{C}{2} \times \dfrac{2\pi r}{2\pi}\\\text{Putting }2\pi r = C:\\\Rightarrow A = \dfrac{C \times C}{4 \pi}\\\Rightarrow A = \dfrac{C^2}{4 \pi}$

Hence, A in terms of C can be represented as:

$A = \dfrac{C^2}{4\pi}$

4 0

3 years ago

Evaluate the integral Integral ∫ from (1,2,3 ) to (5, 7,-2 ) y dx + x dy + 4 dz by finding parametric equations for the line seg

n200080 [17]

$\vec F(x,y,z)=y\,\vec\imath+x\,\vec\jmath+3\,\vec k$

is conservative if there is a scalar function $f(x,y,z)$ such that $\nabla f=\vec F$ . This would require

$\dfrac{\partial f}{\partial x}=y$

$\dfrac{\partial f}{\partial y}=x$

$\dfrac{\partial f}{\partial z}=3$

(or perhaps the last partial derivative should be 4 to match up with the integral?)

From these equations we find

$f(x,y,z)=xy+g(y,z)$

$\dfrac{\partial f}{\partial y}=x=x+\dfrac{\partial g}{\partial y}\implies\dfrac{\partial g}{\partial y}=0\implies g(y,z)=h(z)$

$f(x,y,z)=xy+h(z)$

$\dfrac{\partial f}{\partial z}=3=\dfrac{\mathrm dh}{\mathrm dz}\implies h(z)=3z+C$

$f(x,y,z)=xy+3z+C$

so $\vec F$ is indeed conservative, and the gradient theorem (a.k.a. fundamental theorem of calculus for line integrals) applies. The value of the line integral depends only the endpoints:

$\displaystyle\int_{(1,2,3)}^{(5,7,-2)}y\,\mathrm dx+x\,\mathrm dy+3\,\mathrm dz=\int_{(1,2,3)}^{(5,7,-2)}\nabla f(x,y,z)\cdot\mathrm d\vec r$

$=f(5,7,-2)-f(1,2,3)=\boxed{18}$

8 0

2 years ago

JKL is a straight line.

kirza4 [7]

Answer:

x = 32°

Step-by-step explanation:

∆KLM is an isosceles triangle because it has two equal sides, KL & KM. Therefore, the angles opposite to each of the two equal sides, which are referred to as the base angles are congruent to each other.

m<KML = m<KLM = 58°

m<MKL = 180 - (58 + 58) (Sum of triangle)

m<MKL = 64°

m<JKM = 180 - m<MKL (linear pair theorem)

m<JKM = 180 - 64 (Substitution)

m<JKM = 116°

∆JKM is also an isosceles triangle with two equal sides. Therefore, it's based angles (x & <J) would also be equal to each other.

Thus:

x = ½(180 - m<JKM)

x = ½(180 - 116) (Substitution)

x = 32°

3 0

2 years ago

Transform the equation to isolate x: ax = bx 1. How is the value of x related to the difference of a and b?

cestrela7 [59]

Answer:

The value of x is reciprocal of the difference of a and b.

Step-by-step explanation:

We are given the equation, $ax=bx+1$

On simplifying, we get,

$ax=bx+1$

i.e. $ax-bx=1$

i.e. $(a-b)x=1$

i.e. $x=\frac{1}{a-b}$

So, we get,

The value of x is $\frac{1}{a-b}$ .

That is, the value of x is reciprocal of the difference of a and b.

5 0

2 years ago

Read 2 more answers

Select the correct answer.

crimeas [40]

Answer:

D

Step-by-step explanation:

The absolute value function always returns a positive value, that is

| - a | = | a | = a

Given

8 - | 2g - 5 | ← substitute g = - 3.5 into the expression

= 8 - | - 7 - 5 |

= 8 - | - 12 |

= 8 - 12

= - 4 → D

8 0

2 years ago