document.write( "Question 1187790: P1 (A ∨ B) ⊃ C
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Algebra.Com's Answer #818869 by math_helper(2461) $\"\"$ $\"About$

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document.write( "1. (A v B) --> C         Premise
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document.write( "2. (~A v D) --> E        Premise
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document.write( "// show C v E\r
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document.write( "// I am using a conditional proof, lines prefixed with :: are part
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document.write( "// of the conditional proof.\r
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document.write( "3.:: A                   Conditional Proof (CP) assumption #1
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document.write( "4.:: (A v B)             3, ADDition
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document.write( "5.:: C                   4,1 Modus Ponens (MP)
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document.write( "6.:: ~A                  CP assumption #2
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document.write( "7.:: (~A v D)            6, ADD
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document.write( "8.:: E                   7,2 MP
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document.write( "9.:: C v E               3-8, Proof by Cases (PBC)
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document.write( "10. C v E                3-9, CP\r
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document.write( "// Explanation:
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document.write( "//  Lines 3-5 show that assuming A true results in C true
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document.write( "//  Lines 6-8 show that assuming A false results in E true
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document.write( "//  Line 9 says \"A or ~A\" results in \"C or E\" true. Note
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document.write( "//    that A or ~A must be true.\r
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