Question 1104258
<font color="black" face="times" size="3">
Here is one way to do the derivation
<table border=1><tr><th>Number</th><th>Statement</th><th>Lines Used</th><th>Reason</th></tr><tr><td>1</td><td>(A v B) -&gt; D</td><td></td><td></td></tr><tr><td>2</td><td>D -&gt; (C -&gt; E)</td><td></td><td></td></tr><tr><td>3</td><td>A &amp; C</td><td></td><td></td></tr><tr><td>:.</td><td>E</td><td></td><td></td></tr><tr><td>4</td><td>C &amp; A</td><td>3</td><td>Commutation</td></tr><tr><td>5</td><td>A</td><td>3</td><td>Simplification</td></tr><tr><td>6</td><td>C</td><td>4</td><td>Simplification</td></tr><tr><td>7</td><td>A v B</td><td>5</td><td>Addition</td></tr><tr><td>8</td><td>D</td><td>1,7</td><td>Modus Ponens</td></tr><tr><td>9</td><td>C -&gt; E</td><td>2,8</td><td>Modus Ponens</td></tr><tr><td>10</td><td>E</td><td>9,6</td><td>Modus Ponens</td></tr></table>
</font>