document.write( "Question 251006: Stumped\r
\n" ); document.write( "\n" ); document.write( "C <-> T
\n" ); document.write( "~C -> (~S v ~R)
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\n" ); document.write( "(~D v S) & (~D v R)
\n" ); document.write( "We have to show T \n" ); document.write( "
Algebra.Com's Answer #184838 by Edwin McCravy(20055)\"\" \"About 
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document.write( "1.  C <-> T\r\n" );
document.write( "2.  ~C -> (~S v ~R)\r\n" );
document.write( "3.  ~C -> D\r\n" );
document.write( "4.  (~D v S) & (~D v R)\r\n" );
document.write( "We have to show T\r\n" );
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document.write( "5.  ~D v (S&R)                             Distributive law on 4\r\n" );
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document.write( "6.  ~C -> ~(S&R)                           DeMorgan's law on the right side of 2 \r\n" );
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document.write( "7.  (S & R) -> C                           Contrapositive of 6 \r\n" );
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document.write( "8.  ~D -> C                                Contrapositive of 3\r\n" );
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document.write( "9.  [(S&R) -> C} & (~D -> C)               Conjunction of 7 and 8\r\n" );
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document.write( "10. [~(S&R) v C] & (~~D v C)               Writing conditionals as disjunctions in 9\r\n" );
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document.write( "11. [~(S&R) v C] & (D v C)                 Double negation on D in 10\r\n" );
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document.write( "12. [~(S&R) & D] v C                       Distributive law on 11\r\n" );
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document.write( "13  ~[(S&R v ~D] v C                       DeMorgan's law on the left part of 12\r\n" );
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document.write( "14. (S&R) v ~D                             Commutative law on 5\r\n" );
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document.write( "15. [(S&R) v ~D] & { ~[(S&R) v ~D]  v C }  Conjunction of 14 and 13                          \r\n" );
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document.write( "16.{[(S&R) v ~D] &   ~[(S&R) v ~D]} v C    Associative law on 15\r\n" );
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document.write( "17.    0 v C                               The expression in braces in 16 is a contradiction                      \r\n" );
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document.write( "18.      C                                 The identity law for disjunction in 17\r\n" );
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document.write( "19.      T                                 By biconditional 1\r\n" );
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document.write( "Edwin
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