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3 years ago

Sin(x+pi/4)-sin(x-pi/4)=1 solve the equation

1 answer:

6 0

Sin(α+β)=sin(α)cos(β)+cos(α)sin(β)
sin(α-β)=sin(α)cos(β)-cos(α)sin(β)

$sin(x+ \frac{ \pi }{4} )=sin(x)cos\frac{ \pi }{4} +cos(x)sin\frac{ \pi }{4} \\ sin(x- \frac{ \pi }{4} )=sin(x)cos\frac{ \pi }{4} -cos(x)sin\frac{ \pi }{4} \\ \\ \\sin(x+ \frac{ \pi }{4} )-sin(x- \frac{ \pi }{4} ) =1 \\ sin(x)cos\frac{ \pi }{4} +cos(x)sin\frac{ \pi }{4} -(sin(x)cos\frac{ \pi }{4} -cos(x)sin\frac{ \pi }{4} )=1 \\ sin(x)cos\frac{ \pi }{4} +cos(x)sin\frac{ \pi }{4} -sin(x)cos\frac{ \pi }{4} +cos(x)sin\frac{ \pi }{4} =1 \\ cos(x)sin\frac{ \pi }{4} +cos(x)sin\frac{ \pi }{4} =1 \\$
$2cos(x)sin\frac{ \pi }{4} =1 \\ sin\frac{ \pi }{4} = \frac{ \sqrt{2} }{2} \\ 2cos(x) \frac{ \sqrt{2} }{2} =1 \\ 2 \cdot \frac{ \sqrt{2} }{2}cos(x) =1 \\ \sqrt{2} cos(x)=1 \\$
$cos(x)= \frac{1}{ \sqrt{2} } \\ x=\pm arccos \frac{1}{ \sqrt{2} }+2 \pi k , k \in Z \\ x=\pm \frac{ \pi }{4} +2 \pi k , k \in Z$

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A consumer advocacy group wants to determine whether there is a difference between the proportions of the two leading automobile

podryga [215]

Answer:

The answer is "0.3206".

Step-by-step explanation:

$H_0: p_1 = p_2\\\\H_a: p_1 \neq p_2\\\\\hat{p_1} = \frac{X_1}{N_1} = \frac{53}{400} = 0.1325\\\\\hat{p_1}= \frac{X_2}{N_2} = \frac{78}{500}= 0.156\\\\\hat{p} = \frac{(X_1 + X_2)}{(N_1 + N_2)} = \frac{(53+78)}{(400+500)} = 0.1456$

Testing statistic:

$z = \frac{(\hat{p_1}- \hat{p_2})}{\sqrt{(\hat{p} \times (1-\hat{p}) \times (\frac{1}{N_1} + \frac{1}{N_2}))}}$

$=\frac{(0.1325-0.156)}{\sqrt{(0.1456\times (1-0.1456)\times (\frac{1}{400} + \frac{1}{500}))}}\\\\ = -0.99$

Calculating the P-value Approach

$\text{P-value}= 0.3206$

7 0

2 years ago

Arie ran an equal number of miles each day for 12 days. He ran 60 miles in total.

Nezavi [6.7K]

Answer:

5 miles/day

Step-by-step explanation:

This is a division problem.

(60 miles)/(12 days) = 5 miles/day

7 0

3 years ago

Read 2 more answers

Graph the linear equation

baherus [9]

For the equation
.. x - y = 4
you can divide by 4 to put the equation into intercept form. This form shows you both interecepts at once.
.. x/4 +y/(-4) = 1

The x-intercept is (4, 0).
The y-intercept is (0, -4).

The graph is shown below.

7 0

3 years ago

Plz help i need helppppppp

Goshia [24]

Answer:

1) 36

b) 5

c) 3.0

Step-by-step explanation:

1) The recursive formula that defines the given sequence is

$a_1=12 \\ a_n=a_{n-1}+4.$

That means we keep adding 4 to the subsequent terms:

The sequence will be:

12,16,20,24,28,32,36,...

Therefore the seventh term is 36.

2) The sequence is recursively defined by;

$a_1=20\\ a_n=a_{n-1} - 5$

This means, we have to keep subtracting 5 from the subsequent terms.

The sequence will be;

20,15,10,5,...

Therefore the fourth term is 5

3) The sequence is recursively defined by:

f(n+1)=f(n)+0.5

where f(1)=-1.5

This means that, the subsequent terms can be found by adding 0.5 to the previous terms.

The sequence will be:

-1.5,-1.0,-0.5,0,0.5,1,1.5,2.0,2.5,3.0,....

Therefore f(10)=3.0

8 0

4 years ago

Complete the square and write in standard form. Show all work.What would be the conic section:CircleEllipseHyperbolaParabola

mote1985 [20]

ANSWER

This is an ellipse. The equation is:

$\frac{(x-1)^2}{3^2}+\frac{(y+4)^2}{4^2}=1$

EXPLANATION

We have to complete the square for each variable. To do so, we have to take the first two terms and compare them with the perfect binomial squared formula,

$(a+b)^2=a^2+2ab+b^2$

For x we have to take 16x² and -32x. Since the coefficient of x is not 1, first, we have to factor out the coefficient 16,

$16x^2-32x=16(x^2-2x)$

Now, the first term of the expanded binomial would be x and the second term -2x. Thus, the binomial is,

$(x-1)^2=x^2-2x+1$

To maintain the equation, we have to subtract 1,

$16(x^2-2x+1-1)=16((x-1)^2-1)=16(x-1)^2-16$

Now, we replace (16x² - 32x) from the given equation by this equivalent expression,

$16(x-1)^2-16+9y^2+72y+16=0$

The next step is to do the same for y. We have the terms 9y² + 72y. Again, since the coefficient of y² is not 1, we factor out the coefficient 9,

$9y^2+72y=9(y^2+8y)$

Following the same reasoning as before, we have that the perfect binomial squared is,

$(y+4)^2=y^2+8y+16$

Remember to subtract the independent term to maintain the equation,

$9(y^2+8y)=9(y^2+8y+16-16)=9((y+4)^2-16)=9(y+4)^2-144$

And now, as we did for x, replace the two terms (9y² + 72y) with this equivalent expression in the equation,

$16(x-1)^2-16+9(y+4)^2-144+16=0$

Add like terms,

$\begin{gathered} 16(x-1)^2+9(y+4)^2+(-16-144+16)=0 \\ 16(x-1)^2+9(y+4)^2-144=0 \end{gathered}$

Add 144 to both sides,

$\begin{gathered} 16(x-1)^2+9(y+4)^2-144+144=0+144 \\ 16(x-1)^2+9(y+4)^2=144 \end{gathered}$

As we can see, this is the equation of an ellipse. Its standard form is,

$\frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1$

So the next step is to divide both sides by 144 and also write the coefficients as fractions in the denominator,

$\begin{gathered} \frac{16(x-1)^2}{144}+\frac{9(y+4)^2}{144}=\frac{144}{144} \\ \\ \frac{(x-1)^2}{\frac{144}{16}}+\frac{(y+4)^2}{\frac{144}{9}}=1 \end{gathered}$

Finally, we have to write the denominators as perfect squares, so we identify the values of a and b. 144 is 12², 16 is 4² and 9 is 3²,

$\frac{(x-1)^2}{(\frac{12}{4})^2}+\frac{(y+4)^2}{(\frac{12}{3})^2}=1$

Note that we can simplify a and b,

$\frac{12}{4}=3\text{ and }\frac{12}{3}=4$

Hence, the equation of the ellipse is,

$\frac{(x-1)^2}{3^2}+\frac{(y+4)^2}{4^2}=1$

3 0

1 year ago