document.write( "Question 869791: I've been stuck on this one for hours, any help would be super appreciated!\r
\n" ); document.write( "\n" ); document.write( "Use an ordinary proof (not conditional or indirect proof):
\n" ); document.write( "1. ~N > (~R > C)
\n" ); document.write( "2. R > N
\n" ); document.write( "3. ~C // N \n" ); document.write( "
Algebra.Com's Answer #524405 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
\r\n" );
document.write( "1.  ~N > (~R > C)\r\n" );
document.write( "2.  R > N\r\n" );
document.write( "3.  ~C // N\r\n" );
document.write( "-------------------------------------------------------\r\n" );
document.write( "4.  (~N & ~R) > C                        1      Exportation\r\n" );
document.write( "5.  (~N & ~R) > ~(~C)                    4      Double Negation\r\n" );
document.write( "6.  ~(~N & ~R)                           5,3    Modus Tollens\r\n" );
document.write( "7.  ~(~N) v ~(~R)                        6      De Morgan's Law\r\n" );
document.write( "8.  ~(~N) v R                            7      Double Negation\r\n" );
document.write( "9.  ~N > R                               8      Material Implication\r\n" );
document.write( "10. ~N > N                               9,2    Hypothetical Syllogism\r\n" );
document.write( "11. ~(~N) v N                            10     Material Implication\r\n" );
document.write( "12. N v N                                11     Double Negation\r\n" );
document.write( "13. N                                    12     Tautology\r\n" );
document.write( "
\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
\n" );