document.write( "Question 1205405: 1. C ⊃ (D v A) /~C v D\r
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Algebra.Com's Answer #842193 by mccravyedwin(409) $\"\"$ $\"About$

You can put this solution on YOUR website!

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document.write( "1. C ⊃ (D v A) \r\n" );
document.write( "2. A ⊃ H\r\n" );
document.write( "3. ~H           /~C v D\r\n" );
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document.write( "            | 4. ~(~C v D)  Assumption for Indirect Proof\r\n" );
document.write( "            | 5. ~~C • ~D   4, DeMorgan's law\r\n" );
document.write( "            | 6. C • ~D     5, Double Negation\r\n" );
document.write( "            | 7. C          6, Simplification         \r\n" );
document.write( "            | 8. D v A    1,7, Modus Ponens   \r\n" );
document.write( "            | 9. ~A       2,3, Modus Tollens\r\n" );
document.write( "            |10. A v D      8, Commutation\r\n" );
document.write( "            |11. D       10,9, Disjunctive syllogism\r\n" );
document.write( "            |12. ~D • C     6, Commutation\r\n" );
document.write( "            |13. ~D        12, Simplification\r\n" );
document.write( "            |14. D • ~D 11,13, Conjunction\r\n" );
document.write( "~C v D     lines 4-14   Indirect Proof\r\n" );
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document.write( "Edwin

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