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3 years ago

Why do we need complex numbers, what are conjugates, and why do we need them

Mathematics

1 answer:

alexdok [17]3 years ago

6 0

I guess I can give a brief overview and then you can decide if I should go deeper into these meaning and use.

Complex numbers are useful because in a lot of cases we need to use the square root of a negative number. Ex.

Solve the quadratic equation x^2+x+1=0

We have to use the quadratic formula since its not factorable.

x=[-1+-sqrt(1-4*1*1)]/2

x=-1/2 + or - sqrt(-3)

If we don't have imaginary numbers, we would be stuck because sqrt(-3) wouldn't exist as you cannot take the square root of a negative number.

But with complex numbers we can actually get the answer for that equation as

x=-1/2 + or - sqrt3*i

Which would give us a mean of using this answer to calculate further to get other needs depending on the problem you are solving. If complex number is not a thing, about half of our equations will have undefined answers.

Now conjugates is a more interesting one, on the surface level we are discussing here there is not much its used for except if you have a complex number as a root of a quadratic equation, then the conjugate of that complex number must also be a solution. Again if you want me to go a more in depth just comment down below, because I could write an entire essay on this topic :-)

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Given: bisects ∠MRQ; ∠RMS ≅ ∠RQS

Serggg [28]

Answer:

ΔRMS ≅ ΔRQS by AAS

Step-by-step explanation:

See the diagram attached.

Given that ∠ RMS = ∠ RQS and N is any point on RS and ∠ MRS = ∠ SRQ.

Therefore, between Δ RMS and Δ RQS, we have

(i) ∠ RMS = ∠ RQS {Given}

(ii) ∠ MRS = ∠ SRQ {Also given} and

(iii) RS is the common side.

So, by angle-angle-side i.e. AAS criteria we can write ΔRMS ≅ ΔRQS. (Answer)

8 0

2 years ago

Read 2 more answers

A simulation was conducted using 10 fair six-sided dice, where the faces were numbered 1 through 6. respectively. All 10 dice we

kompoz [17]

Answer:

C) a sample distribution of a sample mean with n = 10

$\mu_{{\overline}{X}} = 3.5$

and $\sigma_{{\overline}{Y}} = 0.38$

Step-by-step explanation:

Here, the random experiment is rolling 10, 6 faced (with faces numbered from 1 to 6) fair dice and recording the average of the numbers which comes up and the experiment is repeated 20 times.So, here sample size, n = 20 .

Let,

$X_{ij}$ = The number which comes up on the ith die on the jth trial.

∀ i = 1(1)10 and j = 1(1)20

Then,

$E(X_{ij})$ = $\frac {1 + 2 + 3 + 4 + 5 + 6}{6}$

= 3.5 ∀ i = 1(1)10 and j = 1(1)20

and,

$E(X^{2}_{ij}$ = $\frac {1^{2} + 2^{2} + 3^{2} + 4^{2} + 5^{2} + 6^{2}}{6}$

= $\frac {1 + 4 + 9 + 16 + 25 + 36}{6}$

= $\frac {91}{6}$

$\simeq$ 15.166667

so, $Var(X_{ij}$ = $(E(X^{2}_{ij} - {(E(X_{ij})}^{2})$

$\simeq 15.166667 - 3.5^{2}$

= 2.91667

and $\sigma_{X_{ij}}$ = $\sqrt {2.91667}[/tex [tex]\simeq 1.7078261036$

Now we get that,

$Y_{j} = \frac {\sum_{j = 1}^{20}X_{ij}}{20}$

We get that $Y_{j}'s$ are iid RV's ∀ j = 1(1)20

Let, ${\overline}{Y} = \frac {\sum_{j = 1}^{20}Y_{j}}{20}$

So, we get that $E({\overline}{Y}) = E(Y_{j})$

= $E(X_{ij}$ for any i = 1(1)10

= 3.5

and,

$\sigma_{({\overline}{Y})} = \frac {\sigma_{Y_{j}}}{\sqrt {20}} = \frac {\sigma_{X_{ij}}}{\sqrt {20}} = \frac {1.7078261036}{\sqrt {20}} [tex]\simeq 0.38$

Hence, the option which best describes the distribution being simulated is given by,

C) a sample distribution of a sample mean with n = 10

$\mu_{{\overline}{X}} = 3.5$

and $\sigma_{{\overline}{Y}} = 0.38$

6 0

2 years ago

If a circle has an arc with the measure of 60° and the length of the arc is 50 in, what is the

Crazy boy [7]

Answer: radius = 47.8 inches

Step-by-step explanation:

An arc is a portion of the circumference of the circle. The formula for determining the length of an arc is expressed as

Length of arc = θ/360 × 2πr

Where

θ represents the central angle.

r represents the radius of the circle.

π is a constant whose value is 3.14

From the information given,

θ = 60 degrees

Length of arc = 50 inches

Therefore,

50 = 60/360 × 2 × 3.14 × r

Cross multiplying by 360, it becomes

18000 = 376.8r

r = 18000/376.8

r = 47.8 inches

8 0

3 years ago

If x^2 = 30, what is the value of x?

Lapatulllka [165]

$x= +\sqrt{30} ~or ~ -\sqrt{30}$
I'm not sure why ± that sybol isn't working
all together you can write $x=±\sqrt{30}$

Ughh just ignore the "A" symbol .-.

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2 years ago

Which is greater .83 or .083?

Serggg [28]

.83 is greater .038 is in the thousands place and .83 is in the hundreds hope this Helped :D

8 0

3 years ago