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# Complete Proof

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Hello Brainmass OTA! I need help working this proof:

(H>B)&-((RvS)vT),(E&F)vH,(Sv-S).-(D.E) / -(D.-B)&H

I need a Proof built. Thank you!

https://brainmass.com/philosophy/logic-critical-thinking/proof-philosophy-logic-sample-239626

## SOLUTION This solution is FREE courtesy of BrainMass!

This was a tricky proof! It took me 33 lines, so, if your professor says he can do it in 19 lines, he must have a more elegant strategy than I found. I made a truth table first to verify that the argument was valid; since the truth table told me the argument was valid, I knew I should be able to work out a proof. I started out by working forward (from the premises that were given) and simplifying as much as possible to see what the basic pieces were that I had available to work with. This is a good strategy to follow when you are not sure how a proof is going to go. Once I got to the simple pieces, I looked ahead at the conclusion and started working backward. On scratch paper, I worked out the equivalences that are now seen in lines 29 to 33 of my finished proof. Once I got to the formula in line 29, I realized that I would be able to use IP (see lines 17 to 28). This combination of forging forward and working backward is often helpful when trying to "bridge" the premises and conclusion in an argument. Attached you will find the truth table (as an Excel file) that I first built to check whether the argument was valid. The completed proof is attached as a Word document. One more recommendation. When you are first learning to do proofs, a good idea is to study completed proofs. So look at the completed proof that I am providing here and read it over, line-by-line, several times until you are completely comfortable with all of the steps. I suggest that you do this with several completed proofs; this will help you become more comfortable with constructing new proofs in the future.

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!