A parabola has the focus at (4, 6) and the directrix y = –6. Which equation represents this parabola?
2 answers:
Answer:
Step-by-step explanation:
If you graph both the focus and the directrix you will see that the directrix is below the focus...12 units below to be exact. The focus is on the vertical line x = 4, so the vertex also has an x coordinate (which is actually h since h and k represent the vertex) of 4. The vertex is exactly halfway between the focus and the directrix, so that means that the vertex is at (4, 0). h = 4, k = 0. The standard form for this parabola (we know it opens upwards since the parabola ALWAYS wraps itself around the focus and is directed away from the directrix) is:
p is the number of units between the focus and the vertex, or the vertex and the directrix (which is the same number of units since the vertex is smack dab in the middle of them!). That means that p = 6. Filling in 6 for p, 4 for h, and 0 for k we have:
and simplify to
which is the first choice you're given.
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Answer:
£714.00
Step-by-step explanation:
The first step is to set up expresssions for the two shares:
Let x = the amount of one share. The other share is 1785 - x. <u>You don't have to worry about which is smaller--that part will work out automatically</u>!
The two shares are in the ratio of 2:3, so set up the proportion
Again, you don't have to worry--you could set up the proportion "upside down" and everything will work out in the end.
Solve the proportion for x by "cross multiplying" -- use the Means-Extremes Property of proportions.
So one share is £714£ and the other is £1785 - £714 = £1071.
The smaller share is £714.
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1 hr 18 minutes and 27 seconds hmmm
there are 60 minutes in 1 hr, thus 18 minutes is 18/60 hrs or 0.3hr.
so 1hr 18min is 1.3 hrs
there are 60 seconds in 1 minute and 60 minutes in 1 hr, thus 60*60 seconds in 1hr, or 3600 seconds, so, 27 seconds is just 27/3600 hrs, or 0.0075 hrs.
so, 1.3 hr or 1.3000 hr for that matter plus 0.0075, is just 1.3075 hrs.
a)
so, they covered 26.2 miles in 1.3075 hrs, so the average speed is just 26.2/1.3075, or about 20.0382409177 miles/hr
b)
there are 60 minutes in 1 hr, thus 18 minutes is 18/60 hrs or 0.3hr.
so 1hr 18min is 1.3 hrs
there are 60 seconds in 1 minute and 60 minutes in 1 hr, thus 60*60 seconds in 1hr, or 3600 seconds, so, 27 seconds is just 27/3600 hrs, or 0.0075 hrs.
so, 1.3 hr or 1.3000 hr for that matter plus 0.0075, is just 1.3075 hrs.
a)
so, they covered 26.2 miles in 1.3075 hrs, so the average speed is just 26.2/1.3075, or about 20.0382409177 miles/hr
b)