Question

law of Detachment or Law of Syllogism or invalid:
1. if an angle is acute, then it is not obtuse
2. 13 years ago

Answer 1

These follow straight from the definitions.

Law of Detachment: If a => b is true and a is true, then b is true.
Law of Syllogism: If a => b and b => c is true, then a => c is true.

From there, you should be able to see that this is the Law of Detachment.

Answer 2

thanks