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4 years ago

On 88 question to leebeth Missed 11 question was has that gread for that test

Mathematics

1 answer:

likoan [24]4 years ago

5 0

assuming the test is worth 100 points.

there were 88 questions in total, she missed 11, meaning she answered 88 - 11 = 77, assuming her grade is those 77 correct ones.

if 88 is the 100%, what is 77 off of it in percentage?

$\bf \begin{array}{ccll} amount&\%\\ \cline{1-2} 88&100\\ 77&x \end{array}\implies \cfrac{88}{77}=\cfrac{100}{x}\implies \cfrac{8}{7}=\cfrac{100}{x} \\\\\\ 8x=700\implies x=\cfrac{700}{8}\implies x=87.5$

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Boats from all along the Atlantic coast were moored at a busy marina one summer day. Of the 14 boats at the marina, 7 were from

Bogdan [553]

Answer:

1/2 Or 7/14

Step-by-step explanation:

14 divided by 7 is 2, which means that 1/2 of the boats that came in were from Rhode Island.

6 0

3 years ago

Sin(x)^4+ cos(x)^4=1/2

posledela

I'll assume that what was meant was $\sin ^4 x + \cos ^4 x = \dfrac{1}{2}$ .

The exponent in the funny place is just an abbreviation: $\sin ^4 x = (\sin x)^4$ .

I hope that's what you meant. Let me know if I'm wrong.

Let's start from the old saw

$\cos^2 x + \sin ^2x = 1$

Squaring both sides,

$(\cos^2 x + \sin ^2x)^2 = 1^2$

$\cos^4 x + 2 \cos ^2 x \sin ^2x +\sin ^4x = 1$

$\cos^4 x + \sin ^4x = 1 - 2 \cos ^2 x \sin ^2x$

So now the original question

$\sin ^4 x + \cos ^4 x = \dfrac{1}{2}$

becomes
$1 - 2 \cos ^2 x \sin ^2x = \dfrac{1}{2}$

$4 \cos ^2 x \sin ^2x = 1$

Now we use the sine double angle formula

$\sin 2x = 2 \sin x \cos x$

We square it to see

$\sin^2 2x = 4\sin^2 x \cos^2 x = 1$

Taking the square root,

$\sin 2x = \pm 1$

Not sure how you want it; we'll do it in degrees.

When we know the sine of an angle, there's usually two angles on the unit circle that have that sine. They're supplementary angles which add to $180^\circ$ . But when the sine is 1 or -1 like it is here, we're looking at $90^\circ$ and $-90^\circ$ , which are essentially their own supplements, slightly less messy.

That means we have two equations:

$\sin 2x = 1 = \sin 90^\circ$

$2x = 90^\circ + 360^\circ k \quad$ integer $k$

$x = 45^\circ + 180^\circ k$

or

$\sin 2x = -1 = \sin -90^\circ$

$2x = -90^\circ+ 360^\circ k$

$x = - 45^\circ + 180^\circ k$

We can combine those for a final answer,

$x = \pm 45^\circ + 180^\circ k \quad$ integer $k$

Check. Let's just check one, how about

$x=-45^\circ + 180^\circ = 135^\circ$

$\sin(135)= 1/\sqrt{2}$

$\sin ^4(135)=(1/\sqrt{2})^4 = 1/4$

$\cos ^4(135)=(-1/\sqrt{2})^4 = 1/4$

$\sin ^4(135^\circ) +\cos ^4(135^\circ) = 1/2 \quad\checkmark$

6 0

3 years ago

3(p+5)-3(p+2) expand and simplify

Katyanochek1 [597]

Answer:

its 9

Step-by-step explanation:

3 0

3 years ago

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Christopher has breakfast at a cafe and the cost of his meal is \$36.00$36.00dollar sign, 36, point, 00. Because of the service,

Leokris [45]

Answer:

His total bill including the tip = $39.6

Step-by-step explanation:

Christopher has breakfast at a cafe and the cost of his meal is $36.00

Because of the service, he wants to leave a 10% tip. This means that he would be paying more than the original cost of the meal. The cost of tip would be determined by multiplying the original cost of the meal by 10%. This becomes

Cost of tip = 10/100 × 36.00 =

0.1× 36.00= $3.6

His total bill including the tip would be sum of the cost of the original bill + cost of the tip. It becomes

36.00 + 3.6 = $39.6

6 0

4 years ago

Please help ill give brainliest :c ASAP

Lisa [10]

Answer

The 3rd number line

Hope this helps.

7 0

3 years ago

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