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3 years ago

Solve the inequality:

Mathematics

1 answer:

Allushta [10]3 years ago

3 0

Answer:

x ≤ 1

Step-by-step explanation:

8 + 4x $\geq$ 12

4x $\geq$ 12 - 8

4x ≥ 4

Dividing both sides by 4 gives;

x ≤ 1

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Use trigonometric substitution to evaluate the integral 13 + 12x − x2 dx . First, write the expression under the radical in an a

SCORPION-xisa [38]

I don't see a square root sign anywhere, so I'll assume the integral is

$\displaystyle\int\sqrt{13+12x-x^2}\,\mathrm dx$

First complete the square:

$13+12x-x^2=49-(6-x)^2=7^2-(6-x)^2$

Now in the integral, substitute

$6-x=7\sin t\implies\mathrm dx=-7\cos t\,\mathrm dt$

so that

$t=\sin^{-1}\left(\dfrac{6-x}7\right)$

Under this change of variables, we have

$7^2-(6-x)^2=7^2-7^2\sin^2t=7^2(1-\sin^2t)=7^2\cos^2t$

so that

$\displaystyle\int\sqrt{13+12x-x^2}\,\mathrm dx=-7\int\sqrt{7^2\cos^2t}\,\cos t\,\mathrm dt=-49\int|\cos t|\cos t\,\mathrm dt$

Under the right conditions, namely that cos(t) > 0, we can further reduce the integrand to

$|\cos t|\cos t=\cos^2t=\dfrac{1+\cos(2t)}2$

$\displaystyle-49\int|\cos t|\cos t\,\mathrm dt=-\frac{49}2\int(1+\cos(2t))\,\mathrm dt=-\frac{49}2\left(t+\frac12\sin(2t)\right)+C$

Expand the sine term as

$\dfrac12\sin(2t)}=\sin t\cos t$

Then

$t=\sin^{-1}\left(\dfrac{6-x}7\right)\implies \sin t=\dfrac{6-x}7$

$t=\sin^{-1}\left(\dfrac{6-x}7\right)\implies \cos t=\sqrt{7^2-(6-x)^2}=\sqrt{13+12x-x^2}$

So the integral is

$\displaystyle-\frac{49}2\left(\sin^{-1}\left(\dfrac{6-x}7\right)+\dfrac{6-x}7\sqrt{13+12x-x^2}\right)+C$

3 0

3 years ago

a train goes 20% farther than an older train in the same amount of time. During the time it takes the other train to go 200 mile

MakcuM [25]

Answer:

240 miles

Step-by-step explanation:

To solve this we need to write an equation. For this problem let d be the distance traveled. We know that the new train (being much more modern than poor old Thomas who is long retired) can go 20% further. To show this we will take 20% of 200 and then add that to the original distance.

Our equation would look something like this:

d=200+(20%·200)

[one more little note: to find percentage take your percent and convert it into a decimal 20%=0.2)

d=200+(0.2·200)

d=200+40

d=240

4 0

2 years ago

What is the slope of the line 6x – 2y – 14 = 0?

fredd [130]

Answer:

Step-by-step explanation:

8 0

2 years ago

Write <img src="https://tex.z-dn.net/?f=%28-%20x%5E%7B2%7D%29%20-4x%2B2" id="TexFormula1" title="(- x^{2}) -4x+2" alt="(- x^{2})

marin [14]

Because the coefficient of x^2 is -1, we know that a will be -1. Knowing that the coefficient of x is -4, we can calculate that p=2. Thus, we have -1(x+2)^2+q is our equation. This is equal to -x^2-4x-4+q. As the constant term must be 2, we can then see that q is 6.

As such, we have -1(x+2)^2+6=0 as our factorization.

To solve this equation, we can use the quadratic formula. Plugging in values, we have:

$\frac{4+-2 \sqrt{6} }{-2}$
which is equal to: (when the fraction is simplified)
$-2+- \sqrt{6}$

7 0

3 years ago

A bag contains 10 red marbles, 8 blue marbles and 2 yellow marbles. Find the theoretical probability of getting a yellow marble.

Rzqust [24]

(number of yellow marbles) / (overall number of marbles)
=
2/20

7 0

2 years ago