tim's piggy bank contains nickels and quarters worth $12.45. he has 69 coins in all. how many of each coins does he have?

A study examined the alertness benefits of higher caffeine intake. In the study, the researchers investigated the link between d

Katyanochek1 [597]

Answer: B. The data represent a sample since the data are a subset of units.

Step-by-step explanation:

A population is the largest group of entire observations that can be made during a study.
A sample is a finite subset of the population that represents the entire population.

Here,

Population = Participants for the study were those who used a popular social networking Web site.

Since the entire data for the "persons used a popular social networking Web site" is not possible.

There have been taken a sample of them.

∴ Correct answer is B. The data represent a sample since the data are a subset of units.

3 0

3 years ago

The center of the circle is at (-2,-7) and its radius is 36.

Vanyuwa [196]

Standard form for circle with radius r and center (h,k) is
(x-h)^2+(y-k)^2=r^2

r=36
center at -2,-7
(x-(-2))^2+(y-(-7))^2=36^2
(x+2)^2+(y+7)^2=1296

firts option

6 0

3 years ago

Which of the following is equivalent to tan2θcos(2θ) for all values of θ for which tan2θcos(2θ) is defined?

Aloiza [94]

Answer:

2sin²θ - tan²θ

Step-by-step explanation:

Given

tan²θcos(2θ)

Required

Simplify

We start by simplifying cos(2θ)

cos(2θ) = cos(θ+θ)

From Cosine formula

cos(A+A) = cosAcosA - sinAsinA

cos(A+A) = cos²A - sin²A

By comparison

cos(2θ) = cos(θ+θ)

cos(2θ) = cos²θ - sin²θ ----- equation 1

Recall that cos²θ + sin²θ = 1

Make sin²θ the subject of formula

sin²θ = 1 - cos²θ

Substitute sin²θ = 1 - cos²θ in equation 1

cos(2θ) = cos²θ - (1 - cos²θ)

cos(2θ) = cos²θ - 1 +cos²θ

cos(2θ) = cos²θ + cos²θ - 1

cos(2θ) = 2cos²θ - 1

Substitute 2cos²θ - 1 for cos(2θ) in the given question

tan²θcos(2θ) becomes

tan²θ(2cos²θ - 1)

Open brackets

2cos²θtan²θ - tan²θ

------------------------

Simplify tan²θ

tan²θ = (tanθ)²

Recall that tanθ = sinθ/cosθ

So, we have

tan²θ = (sinθ/cosθ)²

tan²θ = sin²θ/cos²θ

------------------------

Substitute sin²θ/cos²θ for tan²θ

2cos²θtan²θ - tan²θ becomes

2cos²θ(sin²θ/cos²θ) - tan²θ

Open bracket (cos²θ will cancel out cos²θ) to give

2(sin²θ) - tan²θ

2sin²θ - tan²θ

Hence, the simplification of tan²θcos(2θ) is 2sin²θ - tan²θ

Option E is correct

7 0

3 years ago

Please help me i rlly need help

Mumz [18]

Answer:

3

Step-by-step explanation:

Given a line with points; (2, 5) (3, 8).

1. Find the slope of the given line

The formula for finding the slope is:

$\frac{y_{2}-y_{1} }{x_{2} - x_{1}}$

Substitute in the values;

$x_{1} = 2\\y_{1} = 5\\x_{2} = 3\\y_{2} = 8$

$\frac{8-5}{3-2}$

simplify;

$\frac{3}{1}$

= 3

2. Find the slope of the parallel line;

Remember, when two lines are parallel, they run alongside each other, of infinitely long, but they never touch. Hence two parallel lines have the same slope. Therefore, the slope of a line that is parallel to the given one will also have the same slope as the given one, which is 3.

5 0

3 years ago

0.5=0.4y - 0.25x Solve for y<br>

Ad libitum [116K]

Answer:

y=0.625x+1.25

Step-by-step explanation:

5 0

3 years ago

tim's piggy bank contains nickels and quarters worth $12.45. he has 69 coins in all. how many of each coins does he have?​

tim's piggy bank contains nickels and quarters worth $12.45. he has 69 coins in all. how many of each coins does he have?