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3 years ago

So I’m trying to find out if this is function or not. The problem is is that I’m questioning if this is right

Mathematics

2 answers:

Andrew [12]3 years ago

7 0

Cfrctygjjfeylqlkgrhgze7ojvssyuj

shepuryov [24]3 years ago

5 0

it is a function cause every y has only one X

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Which equation can be solved by using this expression?

Marat540 [252]

Answer:

The correct answer option is B. 2 = 3x + 10x^2

Step-by-step explanation:

We are to determine whether which of the given equations in the answer options can be solved using the following expression:

$x=\frac{-3 \pm\sqrt{(3)^2+4(10)(2)} }{2(10)}$

Here, $a = 10, b = 3$ and $c=-2$ .

These requirements are fulfilled by the equation 4 which is:

$12=3x+10x^2$

Rearranging it to get:

$10x^2+3x-2=0$

Substituting these values of $a,b,c$ in the quadratic formula:

$x= \frac{-b \pm \sqrt{b^2-4ac} }{2a}$

$x= \frac{-3 \pm\sqrt{(3)^2-4(10)(-2)} }{y}$

3 0

3 years ago

Let z=3+i, then find a. Z² b. |Z| c.<img src="https://tex.z-dn.net/?f=%5Csqrt%7BZ%7D" id="TexFormula1" title="\sq

zysi [14]

Given z = 3 + i, right away we can find

(a) square

z ² = (3 + i )² = 3² + 6i + i ² = 9 + 6i - 1 = 8 + 6i

(b) modulus

|z| = √(3² + 1²) = √(9 + 1) = √10

(d) polar form

First find the argument:

arg(z) = arctan(1/3)

Then

z = |z| exp(i arg(z))

z = √10 exp(i arctan(1/3))

z = √10 (cos(arctan(1/3)) + i sin(arctan(1/3))

Any complex number has 2 square roots. Using the polar form from part (d), we have

√z = √(√10) exp(i arctan(1/3) / 2)

and

√z = √(√10) exp(i (arctan(1/3) + 2π) / 2)

Then in standard rectangular form, we have

$\sqrt z = \sqrt[4]{10} \left(\cos\left(\dfrac12 \arctan\left(\dfrac13\right)\right) + i \sin\left(\dfrac12 \arctan\left(\dfrac13\right)\right)\right)$

and

$\sqrt z = \sqrt[4]{10} \left(\cos\left(\dfrac12 \arctan\left(\dfrac13\right) + \pi\right) + i \sin\left(\dfrac12 \arctan\left(\dfrac13\right) + \pi\right)\right)$

We can simplify this further. We know that z lies in the first quadrant, so

0 < arg(z) = arctan(1/3) < π/2

which means

0 < 1/2 arctan(1/3) < π/4

Then both cos(1/2 arctan(1/3)) and sin(1/2 arctan(1/3)) are positive. Using the half-angle identity, we then have

$\cos\left(\dfrac12 \arctan\left(\dfrac13\right)\right) = \sqrt{\dfrac{1+\cos\left(\arctan\left(\dfrac13\right)\right)}2}$

$\sin\left(\dfrac12 \arctan\left(\dfrac13\right)\right) = \sqrt{\dfrac{1-\cos\left(\arctan\left(\dfrac13\right)\right)}2}$

and since cos(x + π) = -cos(x) and sin(x + π) = -sin(x),

$\cos\left(\dfrac12 \arctan\left(\dfrac13\right)+\pi\right) = -\sqrt{\dfrac{1+\cos\left(\arctan\left(\dfrac13\right)\right)}2}$

$\sin\left(\dfrac12 \arctan\left(\dfrac13\right)+\pi\right) = -\sqrt{\dfrac{1-\cos\left(\arctan\left(\dfrac13\right)\right)}2}$

Now, arctan(1/3) is an angle y such that tan(y) = 1/3. In a right triangle satisfying this relation, we would see that cos(y) = 3/√10 and sin(y) = 1/√10. Then

$\cos\left(\dfrac12 \arctan\left(\dfrac13\right)\right) = \sqrt{\dfrac{1+\dfrac3{\sqrt{10}}}2} = \sqrt{\dfrac{10+3\sqrt{10}}{20}}$

$\sin\left(\dfrac12 \arctan\left(\dfrac13\right)\right) = \sqrt{\dfrac{1-\dfrac3{\sqrt{10}}}2} = \sqrt{\dfrac{10-3\sqrt{10}}{20}}$

$\cos\left(\dfrac12 \arctan\left(\dfrac13\right)+\pi\right) = -\sqrt{\dfrac{10-3\sqrt{10}}{20}}$

$\sin\left(\dfrac12 \arctan\left(\dfrac13\right)+\pi\right) = -\sqrt{\dfrac{10-3\sqrt{10}}{20}}$

So the two square roots of z are

$\boxed{\sqrt z = \sqrt[4]{10} \left(\sqrt{\dfrac{10+3\sqrt{10}}{20}} + i \sqrt{\dfrac{10-3\sqrt{10}}{20}}\right)}$

and

$\boxed{\sqrt z = -\sqrt[4]{10} \left(\sqrt{\dfrac{10+3\sqrt{10}}{20}} + i \sqrt{\dfrac{10-3\sqrt{10}}{20}}\right)}$

3 0

3 years ago

Read 2 more answers

Pls help show ALL work

Mkey [24]

Answer:

B. 5.81

Step-by-step explanation:

So to get this answer, you'd first find how much square inches are on the cheese. We know its 9/10 of the pizza and the pizza is 215 square inches. To find out what is 9/10 of the pizza you'd multiply 215 by 9 then divide by 10. That'd leave you with 193.5 then you multiply that by the cost $0.03 then get 5.805 which rounds up to 5.81.

7 0

3 years ago

The Rectangles are similar. Find the value of the variable (Picture Included)

Nady [450]

6/14=x/20 cross multiply and get 14x=120 divide and get 8 2/30

8 0

3 years ago

Read 2 more answers

PLEASE HELP!!

madam [21]

Answer:

k=2/3