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3 years ago

Please explain how to get the answer.

Mathematics

2 answers:

katen-ka-za [31]3 years ago

7 0

Alrighty..

Volume of sphere = 4/3 x (pi)x r^3 .where r is the radius of a circle ..in this case the radius for the smaller circle. and the Volume of the larger one would be 4/3 x (pi)x R^3 .
so when they say the volume if the larger one is Twice the smaller one they're bascially telling you that (4/3x(pi)xR^3 = 2 x (4/3x(pi)xr^3)

When you multiply the formula by two you'd get 4/3x(pi)xR^3= 8/3 x (pi)x r^3

Now solve accordingly by taking 4/3 to the other side.. you'll get sth like this

(pi)R^3 = 2(pi)r^3
Cancel the pi out

now you have R^3 = 2r^3 divide the equation now by r^3
R^3/r^3 =2
you can also write this as (R/r)^3 = 2
take the power cube to the other side to get cube root of 2!!!
therefore R/r= cube root of 2

Hope this helped! :)

Maru [420]3 years ago

3 0

2r=R

Because 2 of "r" make 1 R

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Mashcka [7]

The function modelled by the height (x) of the tree is as follows:
y - 180 = (368 - 180)/(7 - 3) (x - 3)
y - 180 = 47(x - 3) = 47x - 141
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Therefore, after 10 years, the tree will be 47(10) + 39 = 470 + 39 = 509 cm tall

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2 years ago

Use the scale factor to find the area of the enlarged figure. Explain your steps.

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Answer:

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3 years ago

Read 2 more answers

Hello again! This is another Calculus question to be explained.

podryga [215]

Answer:

See explanation.

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Algebra I

Functions

Function Notation

Exponential Property [Rewrite]: $\displaystyle b^{-m} = \frac{1}{b^m}$
Exponential Property [Root Rewrite]: $\displaystyle \sqrt[n]{x} = x^{\frac{1}{n}}$

Calculus

Differentiation

Derivatives
Derivative Notation

Derivative Property [Multiplied Constant]: $\displaystyle \frac{d}{dx} [cf(x)] = c \cdot f'(x)$

Derivative Property [Addition/Subtraction]: $\displaystyle \frac{d}{dx}[f(x) + g(x)] = \frac{d}{dx}[f(x)] + \frac{d}{dx}[g(x)]$

Basic Power Rule:

f(x) = cxⁿ
f’(x) = c·nxⁿ⁻¹

Derivative Rule [Chain Rule]: $\displaystyle \frac{d}{dx}[f(g(x))] =f'(g(x)) \cdot g'(x)$

Step-by-step explanation:

We are given the following and are trying to find the second derivative at x = 2:

$\displaystyle f(2) = 2$

$\displaystyle \frac{dy}{dx} = 6\sqrt{x^2 + 3y^2}$

We can differentiate the 1st derivative to obtain the 2nd derivative. Let's start by rewriting the 1st derivative:

$\displaystyle \frac{dy}{dx} = 6(x^2 + 3y^2)^\big{\frac{1}{2}}$

When we differentiate this, we must follow the Chain Rule: $\displaystyle \frac{d^2y}{dx^2} = \frac{d}{dx} \Big[ 6(x^2 + 3y^2)^\big{\frac{1}{2}} \Big] \cdot \frac{d}{dx} \Big[ (x^2 + 3y^2) \Big]$

Use the Basic Power Rule:

$\displaystyle \frac{d^2y}{dx^2} = 3(x^2 + 3y^2)^\big{\frac{-1}{2}} (2x + 6yy')$

We know that y' is the notation for the 1st derivative. Substitute in the 1st derivative equation:

$\displaystyle \frac{d^2y}{dx^2} = 3(x^2 + 3y^2)^\big{\frac{-1}{2}} \big[ 2x + 6y(6\sqrt{x^2 + 3y^2}) \big]$

Simplifying it, we have:

$\displaystyle \frac{d^2y}{dx^2} = 3(x^2 + 3y^2)^\big{\frac{-1}{2}} \big[ 2x + 36y\sqrt{x^2 + 3y^2} \big]$

We can rewrite the 2nd derivative using exponential rules:

$\displaystyle \frac{d^2y}{dx^2} = \frac{3\big[ 2x + 36y\sqrt{x^2 + 3y^2} \big]}{\sqrt{x^2 + 3y^2}}$

To evaluate the 2nd derivative at x = 2, simply substitute in x = 2 and the value f(2) = 2 into it:

$\displaystyle \frac{d^2y}{dx^2} \bigg| \limits_{x = 2} = \frac{3\big[ 2(2) + 36(2)\sqrt{2^2 + 3(2)^2} \big]}{\sqrt{2^2 + 3(2)^2}}$

When we evaluate this using order of operations, we should obtain our answer:

$\displaystyle \frac{d^2y}{dx^2} \bigg| \limits_{x = 2} = 219$

Topic: AP Calculus AB/BC (Calculus I/I + II)

Unit: Differentiation

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2 years ago

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sveta [45]

First, we are going to find the common ratio of our geometric sequence using the formula: $r= \frac{a_{n}}{a_{n-1}}$ . For our sequence, we can infer that $a_{n}=-20$ and $a_{n-1}=4$ . So lets replace those values in our formula:
$r= \frac{-20}{4}$
$r=-5$

Now that we have the common ratio, lets find the explicit formula of our sequence. To do that we are going to use the formula: $a_{n}=a_{1}*r^{n-1}$ . We know that $a_{1}=4$ ; we also know for our previous calculation that $r=-5$ . So lets replace those values in our formula:
$a_{n}=4*(-5)^{n-1}$

Finally, to find the 9th therm in our sequence, we just need to replace $n$ with 9 in our explicit formula:
$a_{9}=4*(-5)^{9-1}$
$a_{9}=4*(-5)^{8}$
$a_{9}=1562500$

We can conclude that the 9th term in our geometric sequence is 1,562,500

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3 years ago