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3 years ago

The answer I got is not one of the options, and I am very confused, because now I don't know what to do?

Mathematics

1 answer:

Effectus [21]3 years ago

4 0

<span>A’(2, -4); B’(7, -9); C’(-2, -9)
I believe you did it correctly but over the wrong line. You were supposed to do it over line M and it looks like you did it over the X-axis.</span>

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Please help me with these notes

Mekhanik [1.2K]

2y=30+5x
x=6

2y=30+5x
2(5x)=30+5x
10x=30+5x
5x=30
x=6

y=30

6 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

what is the slope of a line that passes through the points (-9,-2) and (-9,-6)? write the answer in simplest form.

muminat

$m = \frac{y2 - y1}{x2 - x1 } \\m = \frac{ - 6 - ( - 2)}{ - 9 - ( - 9)} \\ m = \frac{ - 6 + 2}{ - 9 + 9} \\ m = \frac{ - 4}{0}$

Slope is undefined since there can't be zero in numerator

Please give brainliest

3 0

2 years ago

Ron has 24 coins with a total value of $3.00. The coins are nickels (5 cents) and quarters (25 cents). How many of each coin doe

Vesna [10]

Answer:

Ron has 15 nickels and 9 quarters

Step-by-step explanation:

Create a system of equations where n is the number of nickels and q is the number of quarters he has:

n + q = 24

0.05n + 0.25q = 3

Solve by elimination by multiplying the top equation by -0.25

-0.25n - 0.25q = -6

0.05n + 0.25q = 3

Add them together and solve for n:

-0.2n = -3

n = 15

So, Ron has 15 nickels. Find how many quarters he has by subtracting 15 from 24:

24 - 15

= 9

So, Ron has 15 nickels and 9 quarters.

3 0

3 years ago

Lowest common denominator of 3 5/7 and 4 4/5

IrinaK [193]

Answer: look at the screenshot

Step-by-step explanation:

it has everything you need

6 0

3 years ago