4/5 of a number is 16. What is the number?

What causes changes of states in matter?

Reptile [31]

The answer is A I believe

5 0

3 years ago

What are the coordinates of the point on the directed line segment from (-10, -5) to (5, 1) that partitions the segment into a r

Lera25 [3.4K]

if you make a graph and add the coordinates on the graph you can use that find out how it creates a ratio of 1:2

3 0

3 years ago

Find the values of the six trigonometric functions of 0

Leni [432]

Step-by-step explanation:

sin theta = 12/13

cos theta = 5/13

tan theta = 12/5

cosec theta = 13/12

sec theta = 13/5

cot theta = 5/12

8 0

3 years ago

Arm Span(x) Height(y)

natita [175]

Answer:

Here's what I get.

Step-by-step explanation:

1. Representation of data

I used Excel to create a scatterplot of the data, draw the line of best fit, and print the regression equation.

2. Line of best fit

(a) Variables

I chose arm span as the dependent variable (y-axis) and height as the independent variable (x-axis).

It seems to me that arm span depends on your height rather than the other way around.

(b) Regression equation

The calculation is easy but tedious, so I asked Excel to do it.

For the equation y = ax + b, the formulas are

$a = \dfrac{\sum y \sum x^{2} - \sum x \sumxy}{n\sum x^{2}- \left (\sum x\right )^{2}}\\\\b = \dfrac{n\sumx y - \sum x \sumxy}{n\sum x^{2}- \left (\sum x\right )^{2}}$

This gave the regression equation:

y = 1.0595x - 4.1524

(c) Interpretation

The line shows how arm span depends on height.

The slope of the line says that arm span increases about 6 % faster than height.

The y-intercept is -4. If your height is zero, your arm length is -4 in (both are impossible).

(d) Residuals

$\begin{array}{cccr}&\textbf{Arm Span} & \textbf{Arm Span}&\\\textbf{Height/in} &\textbf{Actual} & \textbf{Predicted}&\textbf{Residual}\\25 & 19 & 22.3 & -3.3\\40 & 41 & 38.2 & 2.8\\55 & 51 & 54.1 & -3.1\\65 & 67 & 62.6 & 4.4\\ \end{array}$

The residuals appear to be evenly distributed above and below the predicted values.

A graph of all the residuals confirms this observation.

The equation usually predicts arm span to within 4 in.

(e) Predictions

(i) Height of person with 66 in arm span

$\begin{array}{rcl}y& = & 1.0595x - 4.1524\\66 & = & 1.0595x - 4.1524\\70.1524 & = & 1.0595x\\x & = & \dfrac{70.1524}{1.0595}\\\\& = & \textbf{66 in}\\\end{array}\\\text{A person with an arm span of 66 in should have a height of about $\large \boxed{\textbf{66 in}}$}$

(ii) Arm span of 74 in tall person

$\begin{array}{rcl}y& = & 1.0595x - 4.1524\\& = & 1.0595\times74 - 4.1524\\& = & 78.4030 - 4.1524\\& = & \textbf{74 in}\\\end{array}\\\text{ A person who is 74 in tall should have an arm span of $\large \boxed{\textbf{74 in}}$}$

6 0

3 years ago

Which equation represents a parabola opening to the right with a vertex at the origin and focus at (9,0) A. X = - 1/36y^2 B. X =

Virty [35]

Answer:

Option C: x = (1/36)*y^2

Step-by-step explanation:

A horizontal parabola is written as

x = f(y) = a*y^2 + b*y + c

If a is positive, the parabola opens to the right.

if a is negative, the parabola opens to the left.

And the vertex of the parabola has the y-value:

y = -b/2a

and the x value

x = f(-b/2a)

For our parabola, we know that:

Opens to the right:

Then the only options left are:

C) x = (1/36)*y^2

D) x = (1/6)*y^2

Because in both cases b = 0, both of the equations have the vertex in the point (0, 0).

Now let's see wich one has a focus at (9, 0)

If the vertex of our equation is:

(h, k)

Then the focus will be:

(h + a, k)

Where a is the directrix of the equation.

Here we know that the vertex is (0, 0) and the focus is (9, 0)

Then:

(0 + a, 0) = (9, 0)

The directrix is 9.

And the directrix is such that:

(x - h)^2 = 4*a*(y - k)

Replacing the values of h and k (both are zero) we get:

x^2 = 4*a*y

And we know that: a = 9

x^2 = 4*9*y

x^2 = 36*y

if we isolate y, we get:

(1/36)*x^2 = y

This is option C.

Then the correct option is C.

8 0

2 years ago