Solve 1/2x-2=9-5x by graphing

Save me the headache

maxonik [38]

$(9\sin2x+9\cos2x)^2=81$

Taking the square root of both sides gives two possible cases,

$9\sin2x+9\cos2x=9\implies\sin2x+\cos2x=1$

or

$9\sin2x+9\cos2x=-9\implies\sin2x+\cos2x=-1$

Recall that

$\sin(\alpha\pm\beta)=\sin\alpha\cos\beta\pm\cos\alpha\sin\beta$

If $\alpha=2x$ and $\beta=\dfrac\pi4$ , we have

$\sin\left(2x+\dfrac\pi4\right)=\dfrac{\sin2x+\cos2x}{\sqrt2}$

so in the equations above, we can write

$\sin2x+\cos2x=\sqrt2\sin\left(2x+\dfrac\pi4\right)=\pm1$

Then in the first case,

$\sqrt2\sin\left(2x+\dfrac\pi4\right)=1\implies\sin\left(2x+\dfrac\pi4\right)=\dfrac1{\sqrt2}$

$\implies2x+\dfrac\pi4=\dfrac\pi4+2n\pi\text{ or }\dfrac{3\pi}4+2n\pi$

(where $n$ is any integer)

$\implies2x=2n\pi\text{ or }\dfrac\pi2+2n\pi$

$\implies x=n\pi\text{ or }\dfrac\pi4+n\pi$

and in the second,

$\sqrt2\sin\left(2x+\dfrac\pi4\right)=-1\implies\sin\left(2x+\dfrac\pi4\right)=-\dfrac1{\sqrt2}$

$\implies2x+\dfrac\pi4=-\dfrac\pi4+2n\pi\text{ or }-\dfrac{3\pi}4+2n\pi$

$\implies2x=-\dfrac\pi2+2n\pi\text{ or }-\pi+2n\pi$

$\implies x=-\dfrac\pi4+n\pi\text{ or }-\dfrac\pi2+n\pi$

Then the solutions that fall in the interval $[0,2\pi)$ are

$x=0,\dfrac\pi4,\dfrac\pi2,\dfrac{3\pi}4,\pi,\dfrac{5\pi}4,\dfrac{3\pi}2,\dfrac{7\pi}4$

5 0

3 years ago

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3.14x(3x5)+34 hjghjhg

alexandr402 [8]

Answer:

81.1 is the answer ..,eksks

7 0

2 years ago

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Which of the following equations has the same solutions as the equations 3x+2y=-12

Marianna [84]

B, C, E, F

<h2>Explanation:</h2>

In this problem, we have the following equation of a line written in Standard form:

$3x+2y=-12$

So we need to choose the equations that has the same solutions as this equation. If we multiply each equation by a constant term and find the same solution as the given equation, then they will have the same solution. This is only true fro options B, C, E and F.

Option B.

$-3x-2y= 12 \\ \\ Multiply \ both \ sides \ by \ -1: \\ \\ (-1)(-3x-2y)=(-1)(12) \\ \\ 3x+2y=-12$

So we get the same given equation. This option is valid!

Option D.

$15x+10y= -60 \\ \\ Multiply \ both \ sides \ by \ 1/5: \\ \\ (\frac{1}{5})(15x+10y)=(\frac{1}{5})(-60) \\ \\ 3x+2y=-12$

So we get the same given equation. This option is valid!

Option E.

$6x+2y= -12 \\ \\ Multiply \ both \ sides \ by \ 1/2: \\ \\ (\frac{1}{2})(6x+2y)=(\frac{1}{2})(-24) \\ \\ 3x+2y=-12$

So we get the same given equation. This option is valid!

Option F.

$1.5x+y= -6 \\ \\ Multiply \ both \ sides \ by \ 2: \\ \\ (2)(1.5x+y)=(2)(-6) \\ \\ 3x+2y=-12$

So we get the same given equation. This option is valid!

For the other options, there is no any constant term that multiplies both sides of the equation and gives us the same given equation.

<h2>Learn more:</h2>

About this subject: brainly.com/question/8810210

#LearnWithBrainly

7 0

3 years ago

Someone help! I’m not good at these problems!

Evgen [1.6K]

Answer:

I beliive it is 16, but haven't done this in a bit haha

Step-by-step explanation:

So bisect means to "split in half" aka segment BD is directly in the middle of triangle ABC. This means we can look at the half of the triangle we know (ABD). We see a 16, so therefore x should be 16.

(again, hopefully I am correct)

5 0

3 years ago

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Ken drew a pair of intersecting rays and marked the angle between them. . . Which of these statements best compares the pair of

ANEK [815]

Ken drew a pair of intersecting rays and marked the angle between them. . . Which of these statements best compares the pair of intersecting rays with the<span>angle</span> I'd say c because the common endpoint is the intersection.

4 0

3 years ago

Solve 1/2x-2=9-5x by graphing ​

Solve 1/2x-2=9-5x by graphing