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Questions tagged [proof-verification]

For questions concerning a specific proof or a specific solution, asking for verification, identifying errors, suggestions for improvement, etc. (You should not use this tag if the question does not contain a proposed proof/solution.)

For questions concerning a specific proof (or a proof sketch) or a solution to some problem; asking a question with this tag indicates one would like answers to respond broadly as to the following:

  • Verification of the proof/solution;
  • Identifying errors in the proof/solution;
  • Suggestions for improving the proof/solution;
  • Alternative approaches.

Also, consider the related tags and .

22798 questions
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How to prove $9^x +1$ is never a square?

This question arose when I was tackling another question, that there exists some function $f(x)=n^x$ such that if $a+b$ is a square, $f(a)+f(b)$ is also a square. I'm trying to disprove it by counter example, with the case $a=1, b=3$.
Rob
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Let $x$ and $y$ be real numbers. If $xy=0,$ then $x=0$ or $y=0.$

When solving this proof would it be okay to say Proof: Let $x,y \in \mathbb{R}.$ We will do a proof by case Case 1. If $x=0,$ then $xy=0y=0$ Case 2. If $y=0,$ then $xy=0x=0$ In each case, $xy=0.$ Or would you prove by contradiction saying: If…
caroline drummond
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1 answer

Disprove That: All birds can fly

I am learning about proof construction. Please let me know what is wrong with this proof? To be proved: There is a bird which can not fly. Proof: Every flying object has wings (Because flying is due to wings). Every bird has wings. (It will not be…
DivineCoder
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1 answer

Stuck on a deductive proof

Premises (p → t) ∨ q r → s (p ∨ q) → r Conclusion s Very new to deductive proofs, I have the 3 above premises and a conclusion. I am confused as to why the answer is not just one line stating that (p ∨ q) → ris equal to…
Peter Wilson
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If $|a|+|b| > |c|+|d|$, is there must $a^2+b^2 > c^2+d^2$?

If $|a|+|b| > |c|+|d|$, is there must $a^2+b^2 > c^2+d^2$?
gonnavis
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1 answer

Determine the veracity of the inequality

Prove if is true or false this statement: If $q > 0$ , is always $q^{-1} > 0$ ? Edited: I tried to elevate both sides to pow of $-1$, but the inequality is indeterminate, due to $0 ^ -1$
ESCM
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((n-1)*(n+1))+1 = n^2 (perfect square when n = integer , but works for all numbers). Is there a proof for this?

I know that n!+1 is a perfect square. But the equation below leads to that as well. ((n-1)*(n+1))+1 = n^2 is a perfect square where n=integer. But is also works for fractions. for example, the square root of 17 = 4.12310..., and (3.12310... *…
Pavook
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