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3 years ago

A pair of skew lines

Mathematics

2 answers:

EastWind [94]3 years ago

6 0

Answer:

Hmmm What about the pair of skew lines lol

Step-by-step explanation:

Could you add more details/options !!!!

-I'd be glad to help <3 !!!!

xxMikexx [17]3 years ago

6 0

I’m pretty sure u have to multiply it

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he expression 34×12 represents a fraction of a circle that is shaded. Which diagram shows the correct shading?

Tomtit [17]

what is the shading

Step-by-step explanation:

???????

5 0

2 years ago

Find the exact value of the expression.<br> tan( sin−1 (2/3)− cos−1(1/7))

Sonja [21]

Answer:

$\tan(a-b)=\frac{2\sqrt{5}-20\sqrt{3}}{5+8\sqrt{15}}$

Step-by-step explanation:

I'm going to use the following identity to help with the difference inside the tangent function there:

$\tan(a-b)=\frac{\tan(a)-\tan(b)}{1+\tan(a)\tan(b)}$

Let $a=\sin^{-1}(\frac{2}{3})$ .

With some restriction on $a$ this means:

$\sin(a)=\frac{2}{3}$

We need to find $\tan(a)$ .

$\sin^2(a)+\cos^2(a)=1$ is a Pythagorean Identity I will use to find the cosine value and then I will use that the tangent function is the ratio of sine to cosine.

$(\frac{2}{3})^2+\cos^2(a)=1$

$\frac{4}{9}+\cos^2(a)=1$

Subtract 4/9 on both sides:

$\cos^2(a)=\frac{5}{9}$

Take the square root of both sides:

$\cos(a)=\pm \sqrt{\frac{5}{9}}$

$\cos(a)=\pm \frac{\sqrt{5}}{3}$

The cosine value is positive because $a$ is a number between $-\frac{\pi}{2}$ and $\frac{\pi}{2}$ because that is the restriction on sine inverse.

So we have $\cos(a)=\frac{\sqrt{5}}{3}$ .

This means that $\tan(a)=\frac{\frac{2}{3}}{\frac{\sqrt{5}}{3}}$ .

Multiplying numerator and denominator by 3 gives us:

$\tan(a)=\frac{2}{\sqrt{5}}$

Rationalizing the denominator by multiplying top and bottom by square root of 5 gives us:

$\tan(a)=\frac{2\sqrt{5}}{5}$

Let's continue on to letting $b=\cos^{-1}(\frac{1}{7})$ .

Let's go ahead and say what the restrictions on $b$ are.

$b$ is a number in between 0 and $\pi$ .

So anyways $b=\cos^{-1}(\frac{1}{7})$ implies $\cos(b)=\frac{1}{7}$ .

Let's use the Pythagorean Identity again I mentioned from before to find the sine value of $b$ .

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

$(\frac{1}{7})^2+\sin^2(b)=1$

$\frac{1}{49}+\sin^2(b)=1$

Subtract 1/49 on both sides:

$\sin^2(b)=\frac{48}{49}$

Take the square root of both sides:

$\sin(b)=\pm \sqrt{\frac{48}{49}$

$\sin(b)=\pm \frac{\sqrt{48}}{7}$

$\sin(b)=\pm \frac{\sqrt{16}\sqrt{3}}{7}$

$\sin(b)=\pm \frac{4\sqrt{3}}{7}$

So since $b$ is a number between $0$ and $\pi$ , then sine of this value is positive.

This implies:

$\sin(b)=\frac{4\sqrt{3}}{7}$

So $\tan(b)=\frac{\sin(b)}{\cos(b)}=\frac{\frac{4\sqrt{3}}{7}}{\frac{1}{7}}$ .

Multiplying both top and bottom by 7 gives:

$\frac{4\sqrt{3}}{1}= 4\sqrt{3}$ .

Let's put everything back into the first mentioned identity.

$\tan(a-b)=\frac{\tan(a)-\tan(b)}{1+\tan(a)\tan(b)}$

$\tan(a-b)=\frac{\frac{2\sqrt{5}}{5}-4\sqrt{3}}{1+\frac{2\sqrt{5}}{5}\cdot 4\sqrt{3}}$

Let's clear the mini-fractions by multiply top and bottom by the least common multiple of the denominators of these mini-fractions. That is, we are multiplying top and bottom by 5:

$\tan(a-b)=\frac{2 \sqrt{5}-20\sqrt{3}}{5+2\sqrt{5}\cdot 4\sqrt{3}}$

$\tan(a-b)=\frac{2\sqrt{5}-20\sqrt{3}}{5+8\sqrt{15}}$

4 0

3 years ago

It is possible none of the choices is the solution?

velikii [3]

Answer:

I am pretty sure the answer would be B!

Hope this helps

Mark me brainliest if I'm right :)

6 0

3 years ago

The probability of winning a certain lottery is 1/77076 for people who play 908 times find the mean number of wins

Alex73 [517]

The mean is 0.0118 approximately. So option C is correct

<h3><u>Solution:</u></h3>

Given that , The probability of winning a certain lottery is $\frac{1}{77076}$ for people who play 908 times

We have to find the mean number of wins

$\text { The probability of winning a lottery }=\frac{1}{77076}$

Assume that a procedure yields a binomial distribution with a trial repeated n times.

Use the binomial probability formula to find the probability of x successes given the probability p of success on a single trial.

$n=908, \text { probability } \mathrm{p}=\frac{1}{77076}$

$\text { Then, binomial mean }=n \times p$

$\begin{array}{l}{\mu=908 \times \frac{1}{77076}} \\\\ {\mu=\frac{908}{77076}} \\\\ {\mu=0.01178}\end{array}$

Hence, the mean is 0.0118 approximately. So option C is correct.

4 0

3 years ago

Al oeste de Albuquerque, Nuevo México, la carretera 40 con rumbo al este es recta y tiene una fuerte pendiente hacia la ciudad.

alexgriva [62]

Usando el concepto de pendiente, se encuentra que el cambio en la distancia horizontal es de 10 pies.

La pendiente de una reta es la <u>razón entre el cambio vertical y el cambio horizontal,</u> o sea, cual el cambio vertical cuando el cambio horizontal es de 1.

En este problema, hay que:

La pendiente es -100, o sea, cuando hay un desplazamiento de un pie por adelante, hay una queda de 100 pies.
Bajado 1000 pies, entonces, aplicando la proporción:

1 pie H -> -100 pies V

x pie H -> -1000 pies V

Aplicando la multiplicación cruzada:

$-100x = -1000$