Brianna babysits on the weekend. She charges $7 per hour. Last weekend she made $63. How many hours did she babysit?

How to find the vertex calculus 2What is the vertex, focus and directrix of x^2 = 6y

son4ous [18]

Solution:

Given:

$x^2=6y$

Part A:

The vertex of an up-down facing parabola of the form;

$\begin{gathered} y=ax^2+bx+c \\ is \\ x_v=-\frac{b}{2a} \end{gathered}$

Rewriting the equation given;

$\begin{gathered} 6y=x^2 \\ y=\frac{1}{6}x^2 \\ \\ \text{Hence,} \\ a=\frac{1}{6} \\ b=0 \\ c=0 \\ \\ \text{Hence,} \\ x_v=-\frac{b}{2a} \\ x_v=-\frac{0}{2(\frac{1}{6})} \\ x_v=0 \\ \\ _{} \\ \text{Substituting the value of x into y,} \\ y=\frac{1}{6}x^2 \\ y_v=\frac{1}{6}(0^2) \\ y_v=0 \\ \\ \text{Hence, the vertex is;} \\ (x_v,y_v)=(h,k)=(0,0) \end{gathered}$

Therefore, the vertex is (0,0)

Part B:

A parabola is the locus of points such that the distance to a point (the focus) equals the distance to a line (directrix)

Using the standard equation of a parabola;

$\begin{gathered} 4p(y-k)=(x-h)^2 \\ \\ \text{Where;} \\ (h,k)\text{ is the vertex} \\ |p|\text{ is the focal length} \end{gathered}$

Rewriting the equation in standard form,

$\begin{gathered} x^2=6y \\ 6y=x^2 \\ 4(\frac{3}{2})(y-k)=(x-h)^2 \\ \text{putting (h,k)=(0,0)} \\ 4(\frac{3}{2})(y-0)=(x-0)^2 \\ Comparing\text{to the standard form;} \\ p=\frac{3}{2} \end{gathered}$

Since the parabola is symmetric around the y-axis, the focus is a distance p from the center (0,0)

Hence,

$\begin{gathered} Focus\text{ is;} \\ (0,0+p) \\ =(0,0+\frac{3}{2}) \\ =(0,\frac{3}{2}) \end{gathered}$

Therefore, the focus is;

$(0,\frac{3}{2})$

Part C:

A parabola is the locus of points such that the distance to a point (the focus) equals the distance to a line (directrix)

Using the standard equation of a parabola;

$\begin{gathered} 4p(y-k)=(x-h)^2 \\ \\ \text{Where;} \\ (h,k)\text{ is the vertex} \\ |p|\text{ is the focal length} \end{gathered}$

Rewriting the equation in standard form,

$\begin{gathered} x^2=6y \\ 6y=x^2 \\ 4(\frac{3}{2})(y-k)=(x-h)^2 \\ \text{putting (h,k)=(0,0)} \\ 4(\frac{3}{2})(y-0)=(x-0)^2 \\ Comparing\text{to the standard form;} \\ p=\frac{3}{2} \end{gathered}$

Since the parabola is symmetric around the y-axis, the directrix is a line parallel to the x-axis at a distance p from the center (0,0).

Hence,

$\begin{gathered} Directrix\text{ is;} \\ y=0-p \\ y=0-\frac{3}{2} \\ y=-\frac{3}{2} \end{gathered}$

Therefore, the directrix is;

$y=-\frac{3}{2}$

3 0

1 year ago

What is the approximate value of 113−−−√ to the nearest tenth?

castortr0y [4]

Answer:

10.6

Step-by-step explanation:

1. First, we need to find which digits √(113) is between, and that would be 10 and 11.

2. Okay, so √(113) is between 10 and 11, meaning 113 is between 100 and 121.

3. Since 113 is a little over half between 100 and 121, let's multiply 10.6 by 10.6 to see how close we are to 113:

$10.6 * 10.6$
$112.36$

4. 112.36 is pretty close to 113, therefore, the dot on the number-line should be placed at 10.6.

7 0

3 years ago

What is the degree of 12x4 - 8x + 4x2 - 3? A. 8 B. 4 C. 3 D. 12

Soloha48 [4]

In this problem, we are asked to determine the degree of the given expression 12X4 - 8X + 4X2 -3. To answer this, first, we need to arrange the mathematical expression in descending order with respect to its power such as the new arrangement will become 12x4 + 4x2 -8x -3. The degree is clearly visible and it is 4. Therefore, the answer to this problem is the letter "B" which is 4.

4 0

3 years ago

Read 2 more answers

d) Jerry, Barry, and Harry went fishing and they each caught a giant fish! Jerry's fish is 62 inches long. Barry's fish is 7 fee

Sauron [17]

No it’s berry 2yards=6feet so they are all smaller than berrys 7foot fish

7 0

3 years ago

If it takes 4 gallons of gas to drive 92 miles how many miles can be driven using 6 gallons

AVprozaik [17]

Answer:

138