For any whole numbers a,b,c is true that (a+b)+c = a+(c+b)? give reason
Answers
Answer:
answer for the given problem is given
Answer:
We are to prove that (a + b) + c = a + (b + c) for all a, b, c belonging to N. We first check the case c = 1 for all a, b. Three applications of definition (given above) give
(a + b) + 1 = (a + b)' = a + b ' = a + (b + 1).
Next, assume the associative law true for a particular value of c and for all a, b. Then we verify it for c' as follows:
(a + b) + c' = (a + b) + (c + 1) (definition)
(a+b)+c′=(a+b)+(c+1) (definition)
=((a+b)+n)+1 (case c=1) ?
We consider (a+b) as a single number; call it A.
We have:
A+(c+1)=(A+c)+1
and it holds by the base case (k=1) already proved.
so,
= ((a + b) + c) + 1 (case c = 1)
= (a + (b + c)) + 1 (induction hypothesis)
= a + ((b + c) + 1) (case c = 1)
= a + (b + (c + 1)) (case c = 1)
= a + (b + c') (definition). proved