Write symbolically: negation and useful denial

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In summary: You can solve it this way, but a solution is not requested, only a formal statement about the set of solutions.
  • #1
ver_mathstats
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Homework Statement


Express the statement symbolically, including a quantification of all variables which makes the universe explicit. Negate the symbolic statement, and express the negation in natural language as a useful denial.

The curves y = 1−x2 and y = 3x-2 intersect.

2. Homework Equations

The Attempt at a Solution


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I am unsure of how to write this statement symbolically.

I assume I start with (∃x∈U) since there is only two point of intersections.

However I do not know where to go from there.

Would I have to equate them to each other?

Would doing 1−x2 = 3x-2 be correct?

Thank you.
 
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  • #2
I would start to write the curves as sets and consider pairs ##(x,y)\in U## not only ##x##:
##P:=\{\,(x,y)\,:\,y+x^2-1=0\,\}## and ##S:=\{\,(x,y)\,:\,y-3x+2=0\,\}##. This way you can handle the intersection as intersection of sets.
 
  • #3
fresh_42 said:
I would start to write the curves as sets and consider pairs ##(x,y)\in U## not only ##x##:
##P:=\{\,(x,y)\,:\,y+x^2-1=0\,\}## and ##S:=\{\,(x,y)\,:\,y-3x+2=0\,\}##. This way you can handle the intersection as intersection of sets.
Thank you for the help, I have not yet learned how to work in sets but I will try to complete my answer using this way. But could this question also be completed if they were to be equated to each other?
 
  • #4
ver_mathstats said:
Thank you for the help, I have not yet learned how to work in sets but I will try to complete my answer using this way. But could this question also be completed if they were to be equated to each other?
You can solve it this way, but a solution is not requested, only a formal statement about the set of solutions. The statement does not have to be true, but unfortunately they do intersect. But again, a statement about a solution is something else than the actual solution. So even if you write it as ##x^2+3x-3=0## then you still have to say something about the solution of this quadratic equation.
 

1. What is the difference between negation and useful denial?

Negation is a logical operation that produces the opposite truth value of a statement. It is represented by the symbol "~" or "¬". Useful denial, on the other hand, is a term used in psychology to describe the act of denying or rejecting a thought or belief that is unhelpful or harmful. It is not represented by a specific symbol, but rather an action or mindset.

2. How do you write negation symbolically?

Negation is symbolically written by placing the "~" or "¬" symbol in front of a statement. For example, if the statement is "I am happy", the negation would be written as "~I am happy" or "¬I am happy".

3. Can you give an example of useful denial?

One example of useful denial is when a person has a negative thought about themselves, such as "I am not good enough". Instead of dwelling on that thought, they can use useful denial to reject it and replace it with a more positive and helpful thought, such as "I am capable and worthy". This can help improve self-esteem and overall well-being.

4. How is negation used in logic and mathematics?

In logic and mathematics, negation is used to form the opposite of a statement. It is an important tool in proving theorems and solving problems. It is also used in conjunction with other logical operators, such as conjunction (AND) and disjunction (OR), to create more complex statements.

5. Is there a limit to how many times negation can be used in a statement?

No, there is no limit to how many times negation can be used in a statement. However, it is important to use it strategically and in a way that makes logical sense. Using too many negations in a statement can make it confusing and difficult to understand.

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