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2 years ago

Please help its due soon ill give brainlest

Mathematics

1 answer:

lara31 [8.8K]2 years ago

4 0

Answer:

r ≈ 7.80 yd

Step-by-step explanation:

The circumference (C) of a circle is calculated as

C = 2πr ( r is the radius )

Here C = 49 , then

2πr = 49 ( divide both sides by 2π )

r = $\frac{49}{2\pi }$ ≈ 7.80 yd ( to the nearest hundredth )

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If someone could help that'd be cool

alukav5142 [94]

Answer:

Step-by-step explanation:

7 0

2 years ago

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PLEASE HELP IM BEGGING Ira B. Scholar, that bizarre math teacher, put the figure at right on a recent test and said,

rewona [7]

Answer:

The perimeter is the distance all the way around the outside of a 2D shape. To calculate the perimeter, sum the lengths of all the sides.

Therefore, perimeter of the triangle = (2x - 8) + (2x + 5) + (30 - 3x)

Collect like terms: 2x + 2x - 3x - 8 + 5 + 30

Combine like terms: x + 27

Therefore, perimeter of triangle = x + 27

We are told that the perimeter is 25:

x + 27 = 25

Subtract 27 from both sides: x = -2

If x = -2, then the side with equation 2x - 8 = (2 x -2) - 8 = -12

A length cannot be negative, therefore the perimeter cannot equal 25.

7 0

2 years ago

Can anybody help plzz?? 65 points

Yakvenalex [24]

Answer:

$\frac{dy}{dx} =\frac{-8}{x^2} +2$

$\frac{d^2y}{dx^2} =\frac{16}{x^3}$

Stationary Points: See below.

General Formulas and Concepts:

Pre-Algebra

Equality Properties

Calculus

Derivative Notation dy/dx

Derivative of a Constant equals 0.

Stationary Points are where the derivative is equal to 0.

1st Derivative Test - Tells us if the function f(x) has relative max or mins. Critical Numbers occur when f'(x) = 0 or f'(x) = undef
2nd Derivative Test - Tells us the function f(x)'s concavity behavior. Possible Points of Inflection/Points of Inflection occur when f"(x) = 0 or f"(x) = undef

Basic Power Rule:

f(x) = cxⁿ
f’(x) = c·nxⁿ⁻¹

Quotient Rule: $\frac{d}{dx} [\frac{f(x)}{g(x)} ]=\frac{g(x)f'(x)-g'(x)f(x)}{g^2(x)}$

Step-by-step explanation:

Step 1: Define

$f(x)=\frac{8}{x} +2x$

Step 2: Find 1st Derivative (dy/dx)

Quotient Rule [Basic Power]: $f'(x)=\frac{0(x)-1(8)}{x^2} +2x$
Simplify: $f'(x)=\frac{-8}{x^2} +2x$
Basic Power Rule: $f'(x)=\frac{-8}{x^2} +1 \cdot 2x^{1-1}$
Simplify: $f'(x)=\frac{-8}{x^2} +2$

Step 3: 1st Derivative Test

Set 1st Derivative equal to 0: $0=\frac{-8}{x^2} +2$
Subtract 2 on both sides: $-2=\frac{-8}{x^2}$
Multiply x² on both sides: $-2x^2=-8$
Divide -2 on both sides: $x^2=4$
Square root both sides: $x= \pm 2$

Our Critical Points (stationary points for rel max/min) are -2 and 2.

Step 4: Find 2nd Derivative (d²y/dx²)

Define: $f'(x)=\frac{-8}{x^2} +2$
Quotient Rule [Basic Power]: $f''(x)=\frac{0(x^2)-2x(-8)}{(x^2)^2} +2$
Simplify: $f''(x)=\frac{16}{x^3} +2$
Basic Power Rule: $f''(x)=\frac{16}{x^3}$

Step 5: 2nd Derivative Test

Set 2nd Derivative equal to 0: $0=\frac{16}{x^3}$
Solve for x: $x = 0$

Our Possible Point of Inflection (stationary points for concavity) is 0.

Step 6: Find coordinates

Plug in the C.N and P.P.I into f(x) to find coordinate points.

x = -2

Substitute: $f(-2)=\frac{8}{-2} +2(-2)$
Divide/Multiply: $f(-2)=-4-4$
Subtract: $f(-2)=-8$

x = 2

Substitute: $f(2)=\frac{8}{2} +2(2)$
Divide/Multiply: $f(2)=4 +4$
Add: $f(2)=8$

x = 0

Substitute: $f(0)=\frac{8}{0} +2(0)$
Evaluate: $f(0)=\text{unde} \text{fined}$

Step 7: Identify Behavior

See Attachment.

Point (-2, -8) is a relative max because f'(x) changes signs from + to -.

Point (2, 8) is a relative min because f'(x) changes signs from - to +.

When x = 0, there is a concavity change because f"(x) changes signs from - to +.

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3 years ago

Write the equation of the circle with center (−3, −2) and (4, 5) a point on the circle.

SSSSS [86.1K]

Your answer should be B

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3 years ago

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a motorboat travels 305km in 5 hours going upstream and 651km in 7 hours going downstream. What is the rate of the boat in still

Ghella [55]

Recall your d = rt, distance = rate * time.

b = speed rate of the boat.

c = speed rate of the current.

keeping in mind that, as the boat goes Upstream, against the current, it's speed is not "b", but is really " b - c ", because the current is subtracting speed from it.

likewise, when the boat is going Downstream, because is going with the current, is really going faster at " b + c ".

$\bf \begin{array}{lccclll}
&\stackrel{km}{distance}&\stackrel{kmh}{rate}&\stackrel{hours}{time}\\
&------&------&------\\
Upstream&305&b-c&5\\
Downstream&651&b+c&7
\end{array}
\\\\\\
\begin{cases}
305=(b-c)(5)\implies 61=b-c\implies 61+c=\boxed{b}\\
651=(b+c)(7)\implies 93=b+c\\
----------------------\\
93=\boxed{61+c}+c
\end{cases}
\\\\\\
93=61+2c\implies 32=2c\implies \cfrac{32}{2}=c\implies 16=c$

what is the speed of the boat? well, 61 + c = b.

6 0

3 years ago