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3 years ago

There is a photo attachedi know its not A

Mathematics

1 answer:

Anna71 [15]3 years ago

6 0

cos 2x=2 cos ^2 x-1

cos x=sqrt(1+cos 2 x)/2

x=67.5

cos 67.5=sqrt(1+ cos 135)/2

=sqrt(1-cos45)/2

=sqrt(1-sqrt(2)/2)/2

=sqrt(2-sqrt2)/4

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Daniel buys a desk that regularly sells for $250 and a desk chair that regularly sells for $145. Both items are on sale at 15% o

erik [133]

Daniel bought a desk which regularly costs $250. It is on sale that is 15% off.

In decimal 15% = 15/100 = 0.15

So after sale the selling price is $ (250 ×(1-0.15))

Also x% sales tax applied to it.

After including sales tax, the price is $(250 ×(1-0.15)) + $ (250 ×(1-0.15)×(x/100))

Now here $(250×(1-0.15) is common to both of them. If we take it out we will get $(250×(1-0.15)×(1+x/100))

So Daniel pays $(250×(1-0.15)×(1+x/100)) for a desk.

Daniel also bought a desk chair whose regular selling price is $145. There is 15% off.

So the price will be $(145 ×(1-0.15))

There is also x% sales tax. So after sales tax Daniel pays

$(145×(1-0.15)) + $(145×(1-0.15)×(x/100)

= $(145×(1-0.15)×(1+x/100))

So the total amount Daniel pays

$(250×(1-0.15)×(1+x/100)) + $(145×(1-0.15)×(1+x/100))

We can take out (1-0.15)×(1+x/100)

$(250+145)×(1-0.15)×(1+x/100) = $(250+145)×(1-0.15)×(100/100 + x/100)

=$(250+145)×(1-0.15)×((100+x)/100)

This is option D. So option D is correct.

$(250+145)×(1-0.15)×(1+x/100)

$395×(0.85)×(1+x/100)

$395×(0.85 + 0.85x/100)

$395×(0.85 + 0.0085x)

$395(0.85) + $395 (0.0085x)

This is option A. So option A is also correct.

We will not get option B and C. So we can say option B and C do not represent the amount that Daniel pays.

4 0

4 years ago

Find the value of -9 - 6 - (-8). 7 -7 -11 11

Dmitry [639]

Answer:

$-7$

Step-by-step explanation:

The given expression is -9 - 6 - (-8)

This question is on PEDMAS

Parenthesis

Exponentiation

Division

Multiplication

Addition

Subtraction

Deal with the parenthesis first;

$-9-6+8$

Now deal with addition;

$-9+2$

We subtract now to obtain;

$-7$

8 0

3 years ago

Read 2 more answers

Hey wyd really really need help with this help plz

attashe74 [19]

Hello!

The answer is B. 2.777.

I hope this helps :))

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3 years ago

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The sum of the ages of two brothers is 46. The younger brother is 10 more than a third of the older brother’s age. Which system

meriva

Answer:

5.5 k Im not sure but I think so yeaf

Step-by-step explanation:

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3 years ago

A device contains two circuits. The second circuit is a backup for the first, so the second is used only when the first has fail

Wittaler [7]

Answer:

Step-by-step explanation:

The pdf of X is given by 3e^x(1-e^-2y). Please check the screenshot for the workings.

The pdf of Y is given by 6e^-2y. Please check the screenshot for the workings.

The expected time the device fails is the expected time Y fails, so we are going to find the expected time of Y which equals to 0.83.

Please check the screenshop for the workings. Thanks

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3 years ago