1.I v (N • F) 2.I ⊃ F / F ------------------------------------------------------- Derivation Line(s) Used Rule Used / Justification 3.( I v N) • (I v F) 1 Dist 4. (I v F) • ( I v N) 3 Comm 5.(I v F) 4 Simp 6.~I ⊃F 5 Impl 7.~F ⊃ ~~I 6 Trans 8.~F ⊃ I 7 D.N. 9.~F ⊃F 2,8 H.S. 10.~~F v F 9 Impl 11.F v F 10 D.N. 12 F 11 Taut [Just want to note that line 9 may confuse some readers because I listed the 2 before the 8 and the form does not match the rule as written. In that case all one needs to do is use line 8 before line 2 for the form to be correct].