- #1
Rayquesto
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Our teacher is teaching calculus 1 with a logic approach. So, he wants us to practice our math logic skills, however, I lack in providing formal methods of validity in operation and to some degree, application. So, here is my solution outline (please tell me what you think)
if operation axiom translational invariance of order:
for all x,y,z€ℝ
x<y => x + z < y + z then the statement:
xy=0 <=> (x=0 or y=0) is true
xy=0 => for all x,y,0€ℝ:[x<y => (x + 0)< (y + 0) or y<x => (y + 0)<(x+0)] by the translation invariance of order
y>0[x€ℝ => 0x = 0] => x>0[y€ℝ => 0y = 0] => for all x,y,0€ℝ:[x<y => (x + 0)< (y + 0) or y<x => (y + 0)<(x+0)] by the multiplication by 0 theorem
Anything else to the proof?
if operation axiom translational invariance of order:
for all x,y,z€ℝ
x<y => x + z < y + z then the statement:
xy=0 <=> (x=0 or y=0) is true
xy=0 => for all x,y,0€ℝ:[x<y => (x + 0)< (y + 0) or y<x => (y + 0)<(x+0)] by the translation invariance of order
y>0[x€ℝ => 0x = 0] => x>0[y€ℝ => 0y = 0] => for all x,y,0€ℝ:[x<y => (x + 0)< (y + 0) or y<x => (y + 0)<(x+0)] by the multiplication by 0 theorem
Anything else to the proof?
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