Hi,

I've been bogging down for a while but got nowhere.

Use rules of inference to show that

$\displaystyle

p\rightarrow\,q

$

$\displaystyle

q\rightarrow\ (r\wedge\ s)

$

$\displaystyle

\neg\ r \rightarrow\ (\neg\ t \vee\ u)

$

$\displaystyle

p \wedge\ t

$

-------------

$\displaystyle

\therefore u

$

Thanks in advance

Regards

TmX