Question on rules of inference

  • Thread starter Thread starter cue928
  • Start date Start date
  • Tags Tags
    Rules
cue928
Messages
129
Reaction score
0

Homework Statement


What rule of inference is used with the following statement:
Kangaroos live in Australia and are marsupials. Therefore, kangaroos are marsupials.

I set this up as p = kangaroos live in Australia and q = kangaroos are marsupials. Therefore, p. To me, it looks like the "simplification" rule, but in our book, simplification is set up as:
p ^ q; therefore, p. Can I change how I defined p and q or am I wrong to begin with?
 
Physics news on Phys.org
cue928 said:

Homework Statement


What rule of inference is used with the following statement:
Kangaroos live in Australia and are marsupials. Therefore, kangaroos are marsupials.

I set this up as p = kangaroos live in Australia and q = kangaroos are marsupials. Therefore, p.
Therefore q.
cue928 said:
To me, it looks like the "simplification" rule, but in our book, simplification is set up as:
p ^ q; therefore, p. Can I change how I defined p and q or am I wrong to begin with?
If your hypothesis is p ^ q, the conclusion can be p or it can be q.

IOW,
p ^ q ==> q
and
p ^ q ==> p
 
Thank you.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...

Similar threads

Back
Top