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3 years ago

Please help!! This is Urgent!!

Mathematics

1 answer:

Akimi4 [234]3 years ago

7 0

Answer:

x=2and x= -- 22

Step-by-step explanation:

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Lim x-> vô cùng ((căn bậc ba 3 (3x^3+3x^2+x-1)) -(căn bậc 3 (3x^3-x^2+1)))

NNADVOKAT [17]

I believe the given limit is

$\displaystyle \lim_{x\to\infty} \bigg(\sqrt[3]{3x^3+3x^2+x-1} - \sqrt[3]{3x^3-x^2+1}\bigg)$

Let

$a = 3x^3+3x^2+x-1 \text{ and }b = 3x^3-x^2+1$

Now rewrite the expression as a difference of cubes:

$a^{1/3}-b^{1/3} = \dfrac{\left(a^{1/3}-b^{1/3}\right)\left(a^{2/3}+a^{1/3}b^{1/3}+b^{2/3}\right)}{\left(a^{2/3}+a^{1/3}b^{1/3}+b^{2/3}\right)} \\\\ = \dfrac{a-b}{a^{2/3}+a^{1/3}b^{1/3}+b^{2/3}}$

Then

$a-b = (3x^3+3x^2+x-1) - (3x^3-x^2+1) \\\\ = 4x^2+x-2$

The limit is then equivalent to

$\displaystyle \lim_{x\to\infty} \frac{4x^2+x-2}{a^{2/3}+(ab)^{1/3}+b^{2/3}}$

From each remaining cube root expression, remove the cubic terms:

$a^{2/3} = \left(3x^3+3x^2+x-1\right)^{2/3} \\\\ = \left(x^3\right)^{2/3} \left(3+\dfrac3x+\dfrac1{x^2}-\dfrac1{x^3}\right)^{2/3} \\\\ = x^2 \left(3+\dfrac3x+\dfrac1{x^2}-\dfrac1{x^3}\right)^{2/3}$

$(ab)^{1/3} = \left((3x^3+3x^2+x-1)(3x^3-x^2+1)\right)^{1/3} \\\\ = \left(\left(x^3\right)^{1/3}\right)^2 \left(\left(3+\dfrac3x+\dfrac1{x^2}-\dfrac1x\right)\left(3-\dfrac1x+\dfrac1{x^3}\right)\right)^{1/3} \\\\ = x^2 \left(9+\dfrac6x-\dfrac1{x^3}+\dfrac4{x^4}+\dfrac1{x^5}-\dfrac1{x^6}\right)^{1/3}$

$b^{2/3} = \left(3x^3-x^2+1\right)^{2/3} \\\\ = \left(x^3\right)^{2/3} \left(3-\dfrac1x+\dfrac1{x^3}\right)^{2/3} \\\\ = x^2 \left(3-\dfrac1x+\dfrac1{x^3}\right)^{2/3}$

Now that we see each term in the denominator has a factor of x ², we can eliminate it :

$\displaystyle \lim_{x\to\infty} \frac{4x^2+x-2}{a^{2/3}+(ab)^{1/3}+b^{2/3}} \\\\ = \lim_{x\to\infty} \frac{4x^2+x-2}{x^2 \left(\left(3+\dfrac3x+\dfrac1{x^2}-\dfrac1{x^3}\right)^{2/3} + \left(9+\dfrac6x-\dfrac1{x^3}+\dfrac4{x^4}+\dfrac1{x^5}-\dfrac1{x^6}\right)^{1/3} + \left(3-\dfrac1x+\dfrac1{x^3}\right)^{2/3}\right)}$

$=\displaystyle \lim_{x\to\infty} \frac{4+\dfrac1x-\dfrac2{x^2}}{\left(3+\dfrac3x+\dfrac1{x^2}-\dfrac1{x^3}\right)^{2/3} + \left(9+\dfrac6x-\dfrac1{x^3}+\dfrac4{x^4}+\dfrac1{x^5}-\dfrac1{x^6}\right)^{1/3} + \left(3-\dfrac1x+\dfrac1{x^3}\right)^{2/3}}$

As x goes to infinity, each of the 1/x ⁿ terms converge to 0, leaving us with the overall limit,

$\displaystyle \frac{4+0-0}{(3+0+0-0)^{2/3} + (9+0-0+0+0-0)^{1/3} + (3-0+0)^{2/3}} \\\\ = \frac{4}{3^{2/3}+(3^2)^{1/3}+3^{2/3}} \\\\ = \frac{4}{3\cdot 3^{2/3}} = \boxed{\frac{4}{3^{5/3}}}$

8 0

3 years ago

Maria spent 15 days traveling in South America how many hours did she’s been traveling in South America

exis [7]

Answer:

360 hours

Step-by-step explanation:

When trying to find the number of hours out of the number of days someone has been doing something, assuming that she spent all 15 days traveling with no rest, you just multiply however many days (In this case, 15 days) by 24 hours.

This gives us the equation 15 times 24, which then equals 360.

A way I check these is that I divide however many hours I got by 24 and make sure it equals our first number.

We get the equation 360 divided by 24, which does, in fact, equal 15.

3 0

3 years ago

Read 2 more answers

Id.k why they removed my last question so here's a question

kondor19780726 [428]

Answer:

a= 2

Step-by-step explanation:

2 x 2=4

7-4=3

8 0

3 years ago

Read 2 more answers

Suppose two parallel lines are cut by a transversal. What angle relationships describe congruent angles in this context?

stiv31 [10]

Answer:

im pretty sure its the 3rd one.

Step-by-step explanation

6 0

3 years ago

Read 2 more answers

The sum of the first terms of an Arithmetic progression (Ap) is 130.if the fifth term is 3times,the first term,find the (a)commo

Nadusha1986 [10]

Answer:

For part a)

130 = 10/2[2a+(10-1)d]

Simplify, u get

2a + 9d = 26.................(1)

Also U5 = a + (5-1)d = 3a

Simplify, u get

a= 2d...................(2)

Substituting for a in equation 1,

2(2d)+9d= 26

Solving for d, we get

d = 2

In part b) substituting for d in equation 2 to get the first term

a = 2(2) = 4

Part c) the no. of terms required can be obtained by solving

28 = 4+(n-1)2

n = 13

5 0

3 years ago