How to find a mathematical formula for these points?

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The discussion revolves around finding a mathematical formula for a function "b" defined by specific points and recursive relationships. The points provided include b(0,0)=1, b(1,0)=3, b(1,1)=4, and b(2,0)=8, with a recursive definition suggesting that each term is the sum of previous terms plus a factor of 2^n. There is confusion regarding whether "b" is a function of one or two variables, and the participants are trying to derive a closed formula from the iterative expression. The conversation emphasizes the challenge of transforming the recursive relationship into a standard formula while acknowledging that multiple formulas can fit the same points. The goal remains to establish a closed formula for the iteration defined by b(n)=2^n + b(0) + b(1) + ... + b(n-1).
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how to find a mathematical formula for these points??

i got these points for this function "b" :
b(0,0)=1
b(1,0)=3
b(1,1)=4
b(2,0)=8

b(0)=1
b(1)=2+1=3
b(2)=4+1+3=8

b(n)=2^n +b(0) +b(1) +b(2) +.. + b(n-2)+b(n-1)

b(n-1)=2^n +b(0) +b(1) +b(2) +.. + b(n-2)

b(n)=b(n-1)+b(n-1) =2*b(n-1)which by the way is wrong because b(1) doesn't equal to 2* b(0)

b(n)=2*b(n-1)how to transform it to the formula
b(n,c)=c+(n-2)*2^(n-1) ?
 
Last edited:
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You have both "b(0,0)" and "b(0)". Is b a function of one variable or two?

Are you just trying to find a function that fits the points (and if so which points: (0,0,0) or (0,0)?) or do you have some other reason to believe that 2^n comes into the equataion?
 


every point ends with zero

b(0,0)=b(0)
b(1,0)=b(1)

the reason i put 2^n into the equation is

b(0)=1 b(0)=1
b(1)=2+1=3 b(1)=2+b(0)
b(2)=4+1+3=8 b(2)=4+b(0)+b(1)so each ne member is the sum of the previous members and 2^n

unfortunately i don't know how build a standard formula from that series expression

b(n,c)=c+(n-2)*2^(n-1) ?
 


So this is NOT a problem of finding a formula that will give those points (there are an infinite number of formulas to fit any finite number of points) but of finding a "closed" formula for that iteration:
bn= 2n+ b0+ b1+ ...+ bn-1 with b0= 1.
 


how do i find a "closed" formula for that iteration:
bn= 2n+ b0+ b1+ ...+ bn-1 with b0= 1.

so ill get

b(n)=(n-2)*2^(n-1)

??
 
Last edited:


i simplified it into
b(n)=2^(n-1) +2*b(n-1) b0=1

what to do now
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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