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3 years ago

Please find the answer

Mathematics

1 answer:

Serggg [28]3 years ago

8 0

Answer:

x^3 + 1/x^3 = 488

Step-by-step explanation:

x^2 + 1/x^2 = 62
x^2 + 1/x^2 + 2 = 64
( adding 2 in both sides )
(x + 1/x ) ^2 = 64
x + 1/x = 8

now,

( x+ 1/x ) ^ 3 = 512
x^3 + 1/x^3 + 3 × x × 1/x ( x + 1/x )
x^3 + 1/x^3 + 3 ( 8 )
( since x + 1/x = 8 )
x^3 + 1/x^3 + 24 = 512
x^3 + 1/x^3 = 488

hence, we got x^3 + 1/x^3 = 488

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A line passes through $A(1,1)$ and $B(100,1000)$. How many other points with integer coordinates are on the line and strictly be

jonny [76]

Answer:

Step-by-step explanation:

Integers are whole numbers or opposite of whole numbers.

The slope is 1.

How?

Change of y is 100-1=99.

Change of x is 100-1=99.

The slope is 99/99=1 or 1/1.

So if we start at (1,1) and we rise 1 and run 1 right, we get (2,2).

If we do that again from (2,2) we get (3,3).

Following the pattern of going up 1 and right from each new location discovered we get all the of these points:

Start (1,1)

(2,2)

(3,3)

(4,4)

(5,5)

(6,6)

....

(96,96)

(97,97)

(98,98)

(99,99)

end (100,100)

So we just need to count all the numbers from 2 to 99.

99-2+1

97+1

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2 years ago

Find two power series solutions of the given differential equation about the ordinary point x = 0. compare the series solutions

monitta

I don't know what method is referred to in "section 4.3", but I'll suppose it's reduction of order and use that to find the exact solution. Take $z=y'$ , so that $z'=y''$ and we're left with the ODE linear in $z$ :

$y''-y'=0\implies z'-z=0\implies z=C_1e^x\implies y=C_1e^x+C_2$

Now suppose $y$ has a power series expansion

$y=\displaystyle\sum_{n\ge0}a_nx^n$
$\implies y'=\displaystyle\sum_{n\ge1}na_nx^{n-1}$
$\implies y''=\displaystyle\sum_{n\ge2}n(n-1)a_nx^{n-2}$

Then the ODE can be written as

$\displaystyle\sum_{n\ge2}n(n-1)a_nx^{n-2}-\sum_{n\ge1}na_nx^{n-1}=0$

$\displaystyle\sum_{n\ge2}n(n-1)a_nx^{n-2}-\sum_{n\ge2}(n-1)a_{n-1}x^{n-2}=0$

$\displaystyle\sum_{n\ge2}\bigg[n(n-1)a_n-(n-1)a_{n-1}\bigg]x^{n-2}=0$

All the coefficients of the series vanish, and setting $x=0$ in the power series forms for $y$ and $y'$ tell us that $y(0)=a_0$ and $y'(0)=a_1$ , so we get the recurrence

$\begin{cases}a_0=a_0\\\\a_1=a_1\\\\a_n=\dfrac{a_{n-1}}n&\text{for }n\ge2\end{cases}$

We can solve explicitly for $a_n$ quite easily:

$a_n=\dfrac{a_{n-1}}n\implies a_{n-1}=\dfrac{a_{n-2}}{n-1}\implies a_n=\dfrac{a_{n-2}}{n(n-1)}$

and so on. Continuing in this way we end up with

$a_n=\dfrac{a_1}{n!}$

so that the solution to the ODE is

$y(x)=\displaystyle\sum_{n\ge0}\dfrac{a_1}{n!}x^n=a_1+a_1x+\dfrac{a_1}2x^2+\cdots=a_1e^x$

We also require the solution to satisfy $y(0)=a_0$ , which we can do easily by adding and subtracting a constant as needed:

$y(x)=a_0-a_1+a_1+\displaystyle\sum_{n\ge1}\dfrac{a_1}{n!}x^n=\underbrace{a_0-a_1}_{C_2}+\underbrace{a_1}_{C_1}\displaystyle\sum_{n\ge0}\frac{x^n}{n!}$

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3 years ago

How do I ace a test that I am not prepared for?

Morgarella [4.7K]

You either start studying now or you fake it and guess and get lucky or you cheat

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2 years ago

The area of a parallelogram is 6 ft' and the height is 3 ft. Find the length of the corresponding base.

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3 years ago

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zubka84 [21]

Answer:

the answer is 104,000

Step-by-step explanation:

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3 years ago

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