Nonnegative Integer Solutions for a+2b+4c=10^30 - Homework Help and Explanation

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In summary, the conversation is about finding the number of nonnegative integer solutions to the equation a+2b+4c=10^30. One person suggests using a multinomial generating function, while the other suggests incrementally varying parameters, specifically focusing on c and using it to find possible values for a and b. It is also noted that the total number of solutions would be (10^30-4c)/2+1 for all c, but this would give an infinite number of solutions. The conversation ends with the acknowledgement that the answer is finite and a further question about whether there are any solutions when 10^30-4c < 0.
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saubbie
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Homework Statement



I need to find the number of nonnegative integer solutions to the equation a+2b+4c=10^30

Homework Equations





The Attempt at a Solution



I was thinking of trying to find perhaps some sort of a multinomial generating function, but am not sure how that will help me. Any suggestions? Thanks.
 
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  • #2
Here are my thoughts:

You can find the total number of solutions by incrementally varying parameters. Since for any solution c will be the least likely to be an integer if you choose arbitrary a and b, varying c and trying to peg possible a's and b's would be the wisest way to proceed. For example:

If c=50, a+2b = 10^30-200. Because once again b is least likely to be an integer if we choose arbitrary a subject to a+2b=10^30-200, b would be the best to vary. Anywhere from b=(10^30-200)/2 to b=0 will have a corresponding a, so there are (10^30-200)/2+1 different solutions for the case c=50. Can you see how this result might generalize to all c?
 
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  • #3
So for all c, there would be (10^30-4c)/2+1 corresponding to every possible c value, but that would give an infinite number of solutions wouldn't it?
 
  • #4
If 10^30-4c < 0, do you have any solutions for non-negative b and a? My approach is simply iteratively inspecting the sum and assuming a varying "chunk" of 10^30 is made up of 4c. The answer is definitely finite.
 

FAQ: Nonnegative Integer Solutions for a+2b+4c=10^30 - Homework Help and Explanation

1. What are nonnegative solutions?

Nonnegative solutions refer to the set of solutions that only include positive numbers or zero. In other words, all the values in the solution set must be greater than or equal to zero.

2. Why are nonnegative solutions important?

Nonnegative solutions are important because they represent a realistic and applicable set of solutions in many real-world situations. For example, nonnegative solutions are often used in optimization problems where negative values do not have a meaningful interpretation.

3. How do you find nonnegative solutions?

The process of finding nonnegative solutions depends on the specific problem. In general, nonnegative solutions can be found by setting all negative variables to zero and then solving for the remaining variables. However, in more complex problems, specialized algorithms or techniques may be required.

4. Can a nonnegative solution be an infinite set?

Yes, a nonnegative solution can be an infinite set. For example, the solution set for the equation x ≥ 0 is an infinite set of all nonnegative real numbers.

5. What is the significance of nonnegative solutions in linear programming?

Nonnegative solutions play a crucial role in linear programming, as they help to determine the feasibility of a problem. In linear programming, the constraints and the objective function must have nonnegative coefficients in order to have a nonnegative solution. Additionally, the optimal solution to a linear programming problem must also be nonnegative.

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