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3 years ago

15

Please Help Me!!!!!! I have a big test tomorrow!!!!!!!! I will give 30 points!!!!!!!!! The expression represents the number of m

iles Celeste rode her bike, and represents the number of miles that Kimiko rode her bike, in hours.
a) Write an expression to show who many more miles Kimiko rode than Celeste.

Answer:

b) If they each rode for 2 hours, how many more miles did Kimiko ride?

Answer:
miles

1 answer:

il63 [147K]3 years ago

4 0

Answer:

For this expression I guessed I would use subtraction because when you subtract Kimiko's miles to Celeste's miles you could see how much faster Kimiko was than Celeste.

Step-by-step explanation:

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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:

<u>Pre-Algebra</u>

Equality Properties

<u>Calculus</u>

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:

<u>Step 1: Define</u>

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

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

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: $f'(x)=\frac{-8}{x^2} +2$

<u>Step 3: 1st Derivative Test</u>

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.

<u>Step 4: Find 2nd Derivative (d²y/dx²)</u>

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: $f''(x)=\frac{16}{x^3}$

<u>Step 5: 2nd Derivative Test</u>

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

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

<u>Step 6: Find coordinates</u>

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

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: $f(0)=\text{unde} \text{fined}$

<u>Step 7: Identify Behavior</u>

<em>See Attachment.</em>

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 +.

3 0

3 years ago

64 miles per hour/ in feet per second

Dafna11 [192]

The answer would be 93.8667 feet per second.

64 miles to feet is 337,920

1 hour = 3600 seconds.

337,920 ÷ 3600 = 93.8667

8 0

3 years ago

abel drew some triangles.his drawing had 21 vertices. how many triangles did he draw?write a division equation to answer the que

Vilka [71]

Triangles have 3 vertices. The total is 21 vertices. 21 / 3 = 7. He drew 7 triangles.

3 0

3 years ago

A miners' cage of mass 420 kg contains 3 miners of total mass 280 kg. The cage

svp [43]

Answer:

5817 Newtons.

Step-by-step explanation:

Total mass of the cage + the miners = 700 Kg which is a downward force of 700g N.

The net downward force = 700g - T where T is the tension (force) in the cable. The g = acceleration due to gravity = 9.81 m s-2.

We calculate the acceleration of the cage by using an equation of motion:

Distance = ut + 1/2 a t^2 where u = initial velocity , t = time and a = acceleration:

75 = 0(t) + 1/2 a (10^2)

50a = 75

a = 1.5 m s-2.

So using Newtons second law of motion

Force = mass * acceleration:

700*9.81 - T = 700 * 1.5

T = 700 * 9.81 - 700*1.5

= 5817 N.

8 0

3 years ago

Name the property or definition illustrated below

dimulka [17.4K]

Answer: Substitution

Step-by-step explanation:

GIVEN:

y=3x

2x+4y=12

Then, 2x+4(3x)=12

-----------------------------------------

Substitution: replacing one variable in terms of another variable.

As we can see from the given aspects, y=3x, and the conclusion expression has no y instead of 3x. This means it represented y in terms of x, which fits the definition of substitution that replaces one variable.

Hope this helps!! :)

6 0

3 years ago