Show that:
[tex]\bigg(\frac{ \sqrt{7} + i \sqrt{3} }{\sqrt{7} - i \sqrt{3} } + {\frac{ \sqrt{7} - i \sqrt{3} }{ \sqrt{7} + i \sqrt{3} } } \bigg) \: is \: real \\ [/tex]
Please answer this question.​

Answers

Answer 1

Step-by-step explanation:

[tex]\large\underline{\sf{Solution-}}[/tex]

Consider,

[tex]\rm \longmapsto\:\dfrac{ \sqrt{7} + i \sqrt{3} }{ \sqrt{7} - i \sqrt{3}} + \dfrac{ \sqrt{7} - i \sqrt{3} }{ \sqrt{7} + i \sqrt{3} } [/tex]

On taking LCM, we get

[tex]\rm \:  =  \: \dfrac{ {( \sqrt{7} + i \sqrt{3})}^{2} + {( \sqrt{7} - i \sqrt{3})}^{2} }{( \sqrt{7} + i \sqrt{3})( \sqrt{7} - i \sqrt{3})} [/tex]

We know,

[tex] \purple{\rm \longmapsto\:\boxed{\tt{ {(x + y)}^{2} + {(x - y)}^{2} = 2( {x}^{2} + {y}^{2})}}} \\ [/tex]

and

[tex] \purple{\rm \longmapsto\:\boxed{\tt{ (x + y)(x - y) = {x}^{2} - {y}^{2} \: }}} \\ [/tex]

So, using these Identities, we get

[tex]\rm \:  =  \: \dfrac{2\bigg[ {( \sqrt{7})}^{2} + {(i \sqrt{3}) }^{2} \bigg]}{ {( \sqrt{7}) }^{2} - {(i \sqrt{3})}^{2} } [/tex]

[tex]\rm \:  =  \: \dfrac{2(7 + 3 {i}^{2})}{7 - {3i}^{2} } [/tex]

We know,

[tex] \purple{\rm \longmapsto\:\boxed{\tt{ {i}^{2} = - 1}}} \\ [/tex]

So, using this, we get

[tex]\rm \:  =  \: \dfrac{2(7 - 3)}{7 + 3} [/tex]

[tex]\rm \:  =  \: \dfrac{2 \times 4}{10} [/tex]

[tex]\rm \:  =  \: \dfrac{4}{5} [/tex]

Hence,

[tex] \red{\rm\implies \:\boxed{\sf{ \dfrac{ \sqrt{7} + i \sqrt{3} }{ \sqrt{7} - i \sqrt{3}} + \dfrac{ \sqrt{7} - i \sqrt{3} }{ \sqrt{7} + i \sqrt{3} } \: is \: purely \: real}}}[/tex]


Related Questions

hi pls help me thanksss
pls provide me with workings thankss :)​

Answers

Step-by-step explanation:

(i)

Using cos(a - b) = cos a cos b + sin a sin b

[tex]\frac{4}{5}[/tex] = cos a cos b + [tex]\frac{1}{5}[/tex]

cos a cos b = [tex]\frac{4}{5} -\frac{1}{5} = \frac{3}{5}[/tex]

(ii)

Using cos(a + b) = cos a cos b - sin a sin b

cos(a + b) = [tex]\frac{3}{5}-\frac{1}{5}=\frac{2}{5}[/tex]

(iii)

Using cot a = [tex]\frac{cos a}{sin a}[/tex]

[tex]=(\frac{cos A}{sin A} )(\frac{cos B}{sin B} )[/tex]

[tex]=\frac{cos A cos B}{sin A sin B}[/tex]

[tex]=\frac{\frac{3}{5} }{\frac{1}{5} }[/tex]  [tex]=\frac{3}{5}[/tex] × [tex]5[/tex]

= 3

please give me a brainliest answer

PLEASE HELP complete the construction a perpendicular line to segment AB through point P.

Answers

Answer:

.

Step-by-step explanation:

sorry i can't help

PLEASE HELP MEE!!! I WILL GIVE YOU THE BRAINLIEST

Answers

Answer:

Domain (-infinity, infinity) Range (-4, infinity)

Step-by-step explanation:

look at the x axis. the graph is going forever out, so infinity.

now look at the y axis. where does it stop? -4. you might need to use [ instead of ( when answering your problem (that just means including) hope this helps!

X+2x-5+6= 0 How would you picture model this to solve for x?

Answers

Hey there!

x + 2x - 5 + 6 = 0

1x + 2x - 5 + 6 = 0

3x + 1 = 0

SUBTRACT 1 to BOTH SIDES

3x + 1 - 1 = 0 - 1

CANCEL out: 1 - 1 because that gives you 0

KEEP: 0 - 1 because that helps solve for the x-value

0 - 1 = -1

NEW EQUATION: 3x = -1

DIVIDE 3 to BOTH SIDES

3x/3 = -1/3

CANCEL out: 3/3 because that gives you 1

KEEP: -1/3 because it gives you the value of x

SIMPLIFY IT

x = -1/3

Therefore, your answer is: x = - 1/3

Good luck on your assignment and enjoy your day!

~Amphitrite1040:)

PLEASE HELP!!

Josh works for MooMoo Milkshakes. The company wants to know what milkshake flavor is the most popular. Today, he surveyed
every third female customer on their favorite milkshake flavor. Eighteen customers
(out of 60 total) were surveyed, and 7 customers
prefer MooChooChocolate, 5 customers prefer VeryStrawberry, and 6 customers prefer BananaBoBanna.
What type of sampling is demonstrated in the situation above?

A. census

B. random sampling

C. negative sampling

D.convenience sampling

Answers

Answer: random sampling

Step-by-step explanation: Random sampling is where each member of the sample is randomly selected from the population. Since Josh chose every third female customer, he randomly chose the sample.

Answer:  B random sampling .

Step-by-step explanation:


(95^5)(92^2) =
A)
9
B)
910
C)
187
D)
1810

Answers

Answer:

I think it is C it is guss

A company makes a profit of $1.38 million. This is $2.54 million more than last year. What was the profit last year?

The answer also asks for us to fill in the blank; "The profit last year was $__ million, so I need help filling in the blank.​

Answers

Answer:  -1.16

The "million" part is already taken care of by your teacher.  

====================================================

Explanation:

x = profit last year (millions of dollars)

x+2.54 = profit this year, which is 2.54 million more than last year

x+2.54 = 1.38

x = 1.38-2.54

x = -1.16

The profit last year was -1.16 million dollars

This is the same as writing -1,160,000 dollars of profit.

A negative profit indicates that the company lost money. This is when the company is spending more than what they earn (i.e. they are in some kind of debt).

Mable earns $180 in 18 hours. at this rate how many dollars will she earn in 30 hours

Answers

Step-by-step explanation:

18 hours = $180

1 hour = 180/18 = $10

so 30 hours = 30 × 10 = $300

please give me a brainliest answer

Two way tables!! Help!!!!
( only the bottom one )

Answers

Answer:

The answer is photo.

Step-by-step explanation:

So:

167 - 66 = 101

So the total of Spain is 101

Now what is Marc’s value for Spain?

33 + 40 = 73

101 - 73 = 28

Marc’s value is 28.

Elli’s value for Portugal is unknown. We know Elli’s total is 57 and her value for Spain is 40. So: 57 - 40 = 17.

Elli’s value for Portugal is 17.

Now what is Marc’s total?

We know Spain is 28 and Portugal is 24. So add them:

28 + 24 = 52

Marc’s total is 52.

Now, what is Raisa’s total. We everyone else’s total and we know it all adds up to 167 so:

57 + 52 = 109

167 - 109 = 58

Raisa’s total is 58.

What is her Portugal value?

58 - 33 = 25

Her Portugal value is 25.

(Factorials)

Solve 5!

_help please_

Answers

Answer:

5*4*3*2*1= 120

you multiply each number to it's previous one till you reach 1

I've tried everywhere to get this answerrrrr ill give brainliest for the correct answer mate!!

Answers

Answer:

list out some of the difference between Mendeleev periodic table modern periodic table plz give ans

Please
Helppp!!


Geometry

Answers

Answer:

m∠6 = 54°

Hope this helps!

Step-by-step explanation:

( 13x+9 ) and angle 4 are congruent meaning the same. That means angles 5 and 8 are also congruent to ( 13x + 9 ).

Angle 5 or angle 8 are Supplementary to angle ( 5x + 9 ) so a Supplementary angle is 180° and we need to find out x.  ( 13x + 9 ) + ( 5x + 9 ) = 18x + 18.

Because Supplementary angles equal 180°, 18x + 18 = 180

18x = 162        x = 162/18       x = 9

Because ∠6 is congruent to angle ( 5x + 9 ), ∠6 = ( 5(9) + 9 )

∠6 = 45 + 9        ∠6 = 54

can someone please help me with this

Answers

Answer:

Perimeter = 18m

Area = 18m²

Step-by-step explanation:

On a rectangle, opposite sides have equal lengths. This means to find the perimeter you would do (3 × 2) + (6 × 2) which is 6 + 12 = 18

The perimeter is 18m

To find the area, you would do length × width. The length is 6 and the width is 3 so 6 × 3 is 18

The area is 18m²

Hope this helps!

PLEASE ANSWER I NEED HELP LOTS OF POINTS

Answers

Easy easy easy easy easy easy easy easy ways

Answer:

blank 1 = 4

blank 2 = -5

blank 3 = -1

Step-by-step explanation:

A salesperson earns a base salary of $400 per week plus 20%
commission on sales. He is offered double his base salary if he'll
accept half his original commission. Graph and label the original deal
and the new deal below. Next to the graph, find when the original deal
is a better choice. Explain your thinking.

Answers

Answer:

(Hope this helps can I pls have brainlist (crown)☺️)

Step-by-step explanation:

For how to graph this, best to look at the guidelines for graphing a break-even formula.

What we do want to know is where these two values equal each other.

So, set:  400 + 0.20X = 800 + 0.10X

Subtract 400 from both sides; also subtract 0.10X from both sides, to get:

0.10X = 400

To solve for "X", divide out both sides by:  0.10, to get:

X = 4,000

What can can glean from this, is that:

(1)  The sales person is better off accepting the higher base salary, up to the point of sales being no more than $4,000;

(2)  The sales person is better off accepting the lower base salary, if their sales are normally expected to exceed $4,000.

PLEASE HELP WE DON'T KNOW THE ANSWERS AND WE ARE ALL FAILING THIS CLASS PLS HELP//// I would like to thank you for helping us so much we greatly apricate this.

Answers

Answer:

leave unknown variables alone on one side. throw the numbers to the other side of the equation by changing sign

Confused ;-; please help me

Answers

Answer:

1)sss

2)asa

3)sas

Step-by-step explanation:

hope this helps

write the volume of a cylinder with a base radius 3 m and height 8 m in terms of pi


Show your work and leave your answer it terms of pi

Answers

Answer:

72π (in terms of pi)

Step-by-step explanation:

V = π·r²·h

Plug in the values.

V = π·3²·8

Solve.

V = 72π

To leave an equation in terms of pi, just square, multiply, and leave pi at the end.

3² = 9·8 = 72

72π

If you need the answer fully simplified, it is 226.19 (rounded up).

PLEASE HELP what is the next term what is A in the sequence and what is the common ratio for 2 4 8 16 32

Answers

Answer:

The next term is 64, a is 2, and the common ratio is 2.

Step-by-step explanation:

Look at what's happening from each number to the next. What do you need to do to get from 2 to 4, or 4 to 8? Multiply by 2. That's your common ratio. To get the next number in the sequence, multiply the last number by the common ratio of 2. 32 x 2 = 64, so the next number in the sequence is 64. "a" is just the very first term, meaning it's 2.

8 liters is the same as how many gallons? round anwer to the nearst tenth

Answers

Answer:

3.785, but rounded to the nearest tenth is 3.8

Step-by-step explanation:

Hope this helps!

Answer 1,76211454 gallons

Step-by-step explanation: if you are in the UK , 1 gallon = 4,54 liters , in America is 3,78

Which graph represents the piecewise-defined function f(x) = { -x + 4, 0 ≤ X< 3
6,
X ≥ 3

Answers

9514 1404 393

Answer:

  (d)

Step-by-step explanation:

The second line of the function is ...

  f(x) = 6, x ≥ 3

This tells you that portion of the graph is the horizontal line y = 6, extending to the right from x = 3, and that there will be a solid dot at (3, 6).

This shows only on the attached graph.

Answer:

4th graph

Step-by-step explanation:

Robin earned $4,581 in 9 weeks. How much does he earn per week?

Answers

Answer:

$509 per week

Step-by-step explanation:

Well, in order to find the unit rate we simply do the following steps:

4,581 ÷ 9 = 509

So to answer the question, each week Robin earns $509.

Hope this helps! : )

Answer:

they earn 509 a week

Step-by-step explanation:4581 divided by 9

hi can anyone help with this question thx
first part of the question is in the pic
second part is here and it is:

York to London is a distance of 175miles
How many miles an hour faster was the first part of the journey?

Answers

Answer:

88 miles per hour

Step-by-step explanation:

12 + 122 = 134 minutes for the entire journey

The total distance was 197 miles.

The avarage speed is the total distance divided by the total time:

Convert the time from minutes to hours dividing it by 60:

134/60 = 2.24 hours

197/2.24 = 87.95 ≈ 88 miles per hour

please if you can i urgently need help thank you very much

Answers

Answer:

1/4

Step-by-step explanation:

2^7/2^9 = 1/2^2

Find the measures of a right triangle with one angle whose measure is 30

Answers

Answer:

The other measure is 60º

Step-by-step explanation:

a triangle= 180º total

a right triangle has one 90º angle

there is a 30º angle given

180-90=90

90-30=60

so 60º

PLS HELP WILL MARK BRAINLIEST
Represent the following algebraically

Answers

Answer:

width = (21 - 2n) ÷ 2 or 21/2 - n

Step-by-step explanation:

To find Width

let's say width is x

so 2x + 2n = 21

take away 2n from both sides

then 2x = 21 - 2n

Divide both sides by 2 to get x on its own

x = 21 - 2n /2

therefore the width of the rectangle is 21 - 2n /2

A diver descends at an average speed of 10.4 m/min. Use rational numbers to write her depth after 3.6 min.

Answers

Answer: it’s just 2.89 there’s nothing else to it

Marc solves the equation Latex: (\sqrt[4]{x})^3=5\textsf{.} His work is shown below. Step 1: Latex: (\sqrt[4]{x})^3=5 ( √ [ 4 ] x ) 3 = 5 Step 2: Latex: x^{\frac{3}{4} }=5 x 3 4 = 5 Step 3: Latex: x^{\frac{3}{4} \cdot \frac{4}{3} }=5^{\frac{4}{3} } x 3 4 ⋅ 4 3 = 5 4 3 Step 4: Latex: x=\sqrt[3]{5 \cdot 5 \cdot 5 \cdot 5} x = √ [ 3 ] 5 ⋅ 5 ⋅ 5 ⋅ 5 Step 5: Latex: x=5\sqrt[3]{\not{5} \cdot \not{5} \cdot\not {5} \cdot 5} x = 5 √ [ 3 ] ¬ 5 ⋅ ¬ 5 ⋅ ¬ 5 ⋅ 5 Step 6: Latex: x=5\sqrt[3]{5} x = 5 √ [ 3 ] 5 Explain what Marc did in steps 4 and 5. Why did he do this? Create your own radical equation and explain how to solve it. Is there an extraneous solution to your equation?

Answers

Based on the calculation, we can say that there is an extraneous solution to the equation

Given the equation solved by Marc expressed as:

[tex](\sqrt[4]{x})^3=5[/tex]

We are to check if the indices equation has an extraneous equation.

According to the law of indices [tex](\sqrt[n]{m} )^a=m^{\frac{a}{n} }[/tex], the expression becomes:

[tex](\sqrt[4]{x})^3=5\\x^\frac{3}{4}=5\\[/tex]

Raise both sides to the power of 4/3 as shown:

[tex](x^\frac{3}{4} )^\frac{4}{3} = 5^\frac{4}{3}\\x^1 = 5^\frac{4}{3}\\x = 5^\frac{4}{3}\\[/tex]

This shows that there is an extraneous solution to the equation

Learn more here: https://brainly.com/question/12232011

need help pls thx..........

Answers

Answer:

170 degree. is the answer

Find f(x) if it is known that f(x-2)=2x-4

Answers

Answer:

f=2

Step-by-step explanation:

f(x-2)=2x-4

divide x-2 to 2x-4

f=2

f(2-2)=4-4

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