I am assuming you mean 4/7 as the sine or cosine cannot be higher than 1.

Lets find <span>θ,
</span>
θ = [sin-1](4/7) = 34.85 °

But lets take into account that this value is the equivalent in Quadrant I.

If Θ lies in Quadrant II , then θ = 180 ° - 34.85 ° = 145.15 °

So cosθ = cos (145.15) = -0.821

4 0

3 years ago

What is the solution to the system of equations? Use any method. {y=−3x+1 {2x+5y=18

Softa [21]

Answer:

So the solution set of the equations are {(-1,4)}

the solution is x = -1 and y = 4

Step-by-step explanation:

Equations given to us are

y = -3x + 1 ..................(i)

2x + 5y = 18 .................(ii)

To find the value of x and y or the solution set of the system of equations

Now in first equation we see that

y = -3x + 1

Putting this value in equation (ii)

which is

2x + 5y = 18

Putting value of y from (i) in it

2x + 5(-3x + 1) = 18

Opening the bracket and multiplying inside

2x -15x + 5 = 18

-13 x + 5 = 18

Subtracting 5 from both sides of the equation

-13x + 5 - 5 = 18 -5

-13x = 13

Dividing both sides by -13

$\frac{-13x}{-13}=\frac{13}{-13}$

Cutting out the same values gives us

x = -1

For value of y

putting value of x in equation (i)

which is

y = -3x + 1

Putting the value

y = -3(-1)+1

y=3+1

y=4

So the solution set of the equations are {(-1,4)}

the solution is x = -1 and y = 4

4 0

3 years ago

Write an equation. Let x be the unknown number.

Assoli18 [71]

3-5x = -5
X =8/5
I hope this helps

4 0

2 years ago

Read 2 more answers

In order for a vaccine to be effective, it should reduce a person's chance of acquiring a disease. Consider a hypothetical vacci

Dmitrij [34]

Answer:

Step-by-step explanation:

Let assume that Suppose the chance of contracting malaria is 10% for those who are not vaccinated ; (since the value) is not given.

Thus;

If the vaccine has no effect, risk of malaria for vaccine and no vaccine are equal to 0.1

Probability of not getting malaria if vaccinated or no vaccinated = 1 - 0.1 = 0.9

Malaria No Malaria Total

Vaccinated 100 * 0.1 = 10 100 * 0.9 = 90 100

No Vaccine 200 * 0.1 = 20 200 * 0.9 = 180 300-100 = 200

Total 20 + 10 = 30 90 + 180 = 270 300

If the vaccine cuts the risk by half, risk of malaria for vaccinated are equal to 0.1/2 = 0.05

Probability of not getting malaria if vaccinated = 1 - 0.05 = 0.95

Malaria No Malaria Total

Vaccinated 100 * 0.05 = 5 100 * 0.95 = 95 100

No Vaccine 200 * 0.1 = 20 200 * 0.9 = 180 300-100 = 200

Total 20 + 5 = 25 90 + 180 = 275 300

3 0

3 years ago