Please help me!! I don't even know where to begin!!

Noideawhatimdoing

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Joined
Nov 8, 2013
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If A=3
B=11
C=107
D= ?


Then what is E?

Im so confused because D isn't filled in....




PLEASE I have no idea how to even begin to figure this out!!!!!!!


please help me!
 
If A=3
B=11
C=107
D= ?


Then what is E?

Im so confused because D isn't filled in....

PLEASE I have no idea how to even begin to figure this out!!!!!!!

please help me!
DON'T PANIC!

If D is not filled in, either (a) it doesn't matter, or (b) you need to find it first.

In case (a), C must depend only on A, and E will have the same relationship to C. This doesn't look hopeful, so it is not likely.

In case (b), C depends on A and B, D depends on B and C, and E depends on C and D. Don't quit yet - first find D, then E.
 
DON'T PANIC!

If D is not filled in, either (a) it doesn't matter, or (b) you need to find it first.

In case (a), C must depend only on A, and E will have the same relationship to C. This doesn't look hopeful, so it is not likely.

In case (b), C depends on A and B, D depends on B and C, and E depends on C and D. Don't quit yet - first find D, then E.

I figured that but I have no idea how these all come to be. I need help figuring out D or even how B and C relate to one other and A.
 
I figured that but I have no idea how these all come to be. I need help figuring out D or even how B and C relate to one other and A.
What is the exact statement of the problem?

You may be missing a clue that is in that statement.
 
If A=3
B=11
C=107
D= ?


Then what is E?

Im so confused because D isn't filled in....
You understand, do you not, that "given" just a list of numbers, there is no reason for the list to have any "rule" at all?
There is absolutely NO reason this list could not have any numbers whatsoever for D and E! Unless there is some other information this is really just an exercise in guessing what the person who made up the list had in mind- an exercise in mind reading!

If we were to take these numbers to be the output of some function at n= 0, 1, 2, 3, and 4, the simplest "rule" would be linear but if y= an+ b, we would have to have y(0)= a(0)+ b= b= 3 and y(1)= a(1)+ b= a+ 3= 11 so that a= 8. But then y(2)= 8(2)+ 3= 16+ 3= 19, not 107.

The simplest function that will give three arbitrary values, here y(0)= 3, y(1)= 11, y(2)= 107, is a quadratic:
y(n)= an^2+ bn+ c. We must have y(0)= c= 3, y(1)= a+ b+ c= 11, y(2)= 4a+ 2b+ c= 107. Since c= 3, a+ b+ c= a+ b+ 3= 11 and 4a+ 2b+ 3= 107 so a+ b= 8 and 4a+ 2b= 104. If we multiply a+ b= 8 by 2, 2a+ 2b= 16, and subtract that from 4a+ 2b= 104, we eliminate b: 2a= 88 so that a= 44. Then a+ b= 44+ b= 8 so b= 8- 44= -36. The "rule" y(n)= 44n^2- 36n+ 3 gives y(0)= 3, y(1)= 44- 36+ 3= 8+ 3= 11, and y(2)= 44(4)- 36(2)+ 3= 176- 72+ 3= 104+3= 107. Now calculate y(3) and y(4) to find D and E.

HOWEVER, this is one possible rule to give these values for A, B, and C. There is no way of knowing what the person who made up this problem had in mind.


PLEASE I have no idea how to even begin to figure this out!!!!!!!


please help me!
 
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