Rule of Replacement

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I am in Intro to Logic and I cannot for the life of me figure out these 4 problems. Can someone please help me out??? I am using symbles where I can, bit I need to use words for others.

1) Without using Disjunctive Syllogism
M v W
~W
There-for M

2) Without using absorption
A > (A and D)
there-for A > D

3) T if and only if (L > K)
~N and K
there-for T

4 Without the Distjunctive form of Equiv
M and W
There-for M if and only if W

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While willing to admit that your post can justifiably be described as the best post so far in this thread, i suggest you might want to copy that post, and start and start a new thread asking for the answer. You're unlikely to get a cogent answer in this venue.

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@ABP,

These identities can be proved by the method of "backward fell swoop".

The truth table for P>Q only has a 0 when P=1 and Q=0, therefore if 0 is assigned to Q and P turns out to be 0 irrespective of truth values assigned to components of P, the identity is valid.

e.g. (1)M v W.~W >M

Put M=0
Thus because 0v1.0 or ov0.1 both=0, the identity holds.

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@ABP,

ABP wrote:

I am in Intro to Logic and I cannot for the life of me figure out these 4 problems. Can someone please help me out??? I am using symbles where I can, bit I need to use words for others.

1) Without using Disjunctive Syllogism
M v W
~W
There-for M

2) Without using absorption
A > (A and D)
there-for A > D

3) T if and only if (L > K)
~N and K
there-for T

4 Without the Distjunctive form of Equiv
M and W
There-for M if and only if W

Is there some reason you are not allowed to use those rules of inference? What rules are you allowed to use, then? Unless I know what system is being used, I cannot ever try to answer.

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Rule of Replacement

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