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3 years ago

Evaluate |-a^2|, given a = 5, b = -3, and c = -2.

Mathematics

2 answers:

geniusboy [140]3 years ago

7 0

The sunset is 25. how this helps!

garik1379 [7]3 years ago

7 0

|-a^2|= |-5^2|= |25|= 25

You basically substitute the values for the letters. -5 x -5 =25 then you find the absolute value which is 25.

****Is this the whole problem or only half because you gave the values for b and c but there was only a.

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Can somebody explain how these would be done? The selected answer is incorrect, and I was told "Nice try...express the product b

trapecia [35]

Answer:

Solution ( Second Attachment ) : - 2.017 + 0.656i

Solution ( First Attachment ) : 16.140 - 5.244i

Step-by-step explanation:

Second Attachment : The quotient of the two expressions would be the following,

$6\left[\cos \left(\frac{2\pi }{5}\right)+i\sin \left(\frac{2\pi \:}{5}\right)\right]$ ÷ $2\sqrt{2}\left[\cos \left(\frac{-\pi }{2}\right)+i\sin \left(\frac{-\pi \:}{2}\right)\right]$

So if we want to determine this expression in standard complex form, we can first convert it into trigonometric form, then apply trivial identities. Either that, or we can straight away apply the following identities and substitute,

( 1 ) cos(x) = sin(π / 2 - x)

( 2 ) sin(x) = cos(π / 2 - x)

If cos(x) = sin(π / 2 - x), then cos(2π / 5) = sin(π / 2 - 2π / 5) = sin(π / 10). Respectively sin(2π / 5) = cos(π / 2 - 2π / 5) = cos(π / 10). Let's simplify sin(π / 10) and cos(π / 10) with two more identities,

( 1 ) $\cos \left(\frac{x}{2}\right)=\sqrt{\frac{1+\cos \left(x\right)}{2}}$

( 2 ) $\sin \left(\frac{x}{2}\right)=\sqrt{\frac{1-\cos \left(x\right)}{2}}$

These two identities makes sin(π / 10) = $\frac{\sqrt{2}\sqrt{3-\sqrt{5}}}{4}$ , and cos(π / 10) = $\frac{\sqrt{2}\sqrt{5+\sqrt{5}}}{4}$ .

Therefore cos(2π / 5) = $\frac{\sqrt{2}\sqrt{3-\sqrt{5}}}{4}$ , and sin(2π / 5) = $\frac{\sqrt{2}\sqrt{5+\sqrt{5}}}{4}$ . Substitute,

$6\left[ \left\frac{\sqrt{2}\sqrt{3-\sqrt{5}}}{4}+i\left\frac{\sqrt{2}\sqrt{5+\sqrt{5}}}{4}\right]$ ÷ $2\sqrt{2}\left[\cos \left(\frac{-\pi }{2}\right)+i\sin \left(\frac{-\pi \:}{2}\right)\right]$

Remember that cos(- π / 2) = 0, and sin(- π / 2) = - 1. Substituting those values,

$6\left[ \left\frac{\sqrt{2}\sqrt{3-\sqrt{5}}}{4}+i\left\frac{\sqrt{2}\sqrt{5+\sqrt{5}}}{4}\right]$ ÷ $2\sqrt{2}\left[0-i\right]$

And now simplify this expression to receive our answer,

$6\left[ \left\frac{\sqrt{2}\sqrt{3-\sqrt{5}}}{4}+i\left\frac{\sqrt{2}\sqrt{5+\sqrt{5}}}{4}\right]$ ÷ $2\sqrt{2}\left[0-i\right]$ = $-\frac{3\sqrt{5+\sqrt{5}}}{4}+\frac{3\sqrt{3-\sqrt{5}}}{4}i$ ,

$-\frac{3\sqrt{5+\sqrt{5}}}{4}$ = $-2.01749\dots$ and $\:\frac{3\sqrt{3-\sqrt{5}}}{4}$ = $0.65552\dots$

= $-2.01749+0.65552i$

As you can see our solution is option c. - 2.01749 was rounded to - 2.017, and 0.65552 was rounded to 0.656.

________________________________________

First Attachment : We know from the previous problem that cos(2π / 5) = $\frac{\sqrt{2}\sqrt{3-\sqrt{5}}}{4}$ , sin(2π / 5) = $\frac{\sqrt{2}\sqrt{5+\sqrt{5}}}{4}$ , cos(- π / 2) = 0, and sin(- π / 2) = - 1. Substituting we receive a simplified expression,

$6\sqrt{5+\sqrt{5}}-6i\sqrt{3-\sqrt{5}}$

We know that $6\sqrt{5+\sqrt{5}} = 16.13996\dots$ and $-\:6\sqrt{3-\sqrt{5}} = -5.24419\dots$ . Therefore,

Solution : $16.13996 - 5.24419i$

Which rounds to about option b.

7 0

3 years ago

Please help, I’ll mark you as brainliest!!!!

DerKrebs [107]

It’s D, $45.00!!!!!!!!!

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3 years ago

Select the correct answer.

Anna71 [15]

1. To the question whether it is a good idea to design a drink can from a solid nonmetal, the answer is <u>No, because nonmetals lack luster</u>.

<h3>The Luster in Nonmetal</h3>

Non-metals do not have luster because they cannot reflect light from their surface with their dull appearances. Diamond and iodine are two exceptions to lustrous non-metals.

2. The reason it is not a good idea designing a drink can from a solid nonmetal is <u>No, because nonmetals are brittle.</u> Generally, solid nonmetals are known to be <u>dull and brittle</u>. They can easily break into pieces.

Thus, non-metals are <u>not ductile or malleable</u>.

Learn more about solid nonmetal here: brainly.com/question/825947

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3 years ago

I gotta have this until 3:30pm please help-

Alecsey [184]

Answer:

They are, because similarity means that the ratio of the sides are equal and they are proportionate.

Step-by-step explanation:

If you look at the graph, you can count 2 units from the smaller diamond/rhombus to the other diamond/rhombus. If you count the amount of units on each side, you will find that they are not equal, however they should be proportional if you calculate the angles of 90°.

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3 years ago

Five snails are having a race. The snail's speeds are given in the table. Which two snails are going the same rate of speed?

kobusy [5.1K]

Answer:

2 1/5 for alice

4 3/14 for Bert

5 for Carl

5 for Eva

5 1/2 for Dennis

Carl and Eva

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3 years ago