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3 years ago

Write the equation for a parabola with a focus at ( 7, 2) and a directrix at y = -2 y = ?

1 answer:

5 0

A parabola with an equation, y2 = 4ax has its vertex at the origin and opens to the right.
It's not just the '4' that is important, it's '4a' that matters.
This type of parabola has a directrix at x = -a, and a focus at (a, 0). By writing the equation as it is, the position of the directrix and focus are readily identifiable.
For example, y2 = 2.4x doesn't say a great deal. Re-writing the equation of the parabola as y2 = 4*(0.6)x tells us immediately that the directrix is at x = -0.6 and the focus is at (0.6, 0)

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Question 4 plz show ALL STEPS

scoray [572]

Part (a)

Locate x = -1 on the x axis. Draw a vertical line through this x value until you reach the f(x) curve. Then move horizontally until you reach the y axis. You should arrive at y = 4. Check out the diagram below to see what I mean.

Since f(-1) = 4, this means we can then say

g( f(-1) ) = g( 4 ) = 4

To evaluate g(4), we'll follow the same idea as what we did with f(x). However, we'll start at x = 4 and draw a vertical line until we reach the g(x) curve this time.

<h3>Answer: 4</h3>

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Part (b)

We use the same idea as part (a)

f(-2) = 5

g( f(-2) ) = g(5) = 6

<h3>Answer: 6</h3>

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Part (c)

Same idea as the last two parts. We start on the inside and work toward the outside. Keep in mind that g(x) is now the inner function for this part and for part (d) as well.

g(1) = -2

f( g(1) ) = f(-2) = 5

<h3>Answer: 5</h3>

==========================================================

Part (d)

Same idea as part (c)

g(2) = 0

f( g(2) ) = f( 0 ) = 3

<h3>Answer: 3</h3>

6 0

3 years ago

9 less than a number can be written as

Liono4ka [1.6K]

Answer:

9 less can be written as -9

7 0

3 years ago

Read 2 more answers

Find the reciprocal

Sav [38]

Answer:

Depends on what number(s)/fraction(s) your working with.

Step-by-step explanation:

Find the reciprocal of a fraction by flipping it. The definition of "reciprocal" is simple. To find the reciprocal of any number, just calculate "1 ÷ (that number)." For a fraction, the reciprocal is just a different fraction, with the numbers "flipped" upside down (inverted).

3 0

3 years ago

In early 2016 there were about 80 devil's line ving on the maria island of the total of 75% are offspring from the previous two

Tju [1.3M]

Answer: 60 devil offspring.

Step-by-step explanation:

The total number of devils in the Island is 80.

Out of this 80, 75% are offspring from the two previous breeding seasons.

This percentage in a whole number is what the question requires.

The number of offspring from previous seasons is:

= Percent of offspring from previous seasons * Total number of devils

= 75% * 80

= 60 devil offspring.

4 0

3 years ago

Suppose we want to choose 7 colors, without replacement, from 9 distinct colors

Digiron [165]

The number of ways to choose the colors is 36

<h3>How to determine the number of ways?</h3>

The given parameters are:

Colors = 9

Colors to choose = 7

Since order does not matter, then it is combination

This is calculated using:

$^nC_r = \frac{n!}{(n - r)!r!}$

This gives

$^nC_r = \frac{9!}{7!2!}$

Evaluate

$^nC_r = 36$

Hence, the number of ways is 36