Given the aim of this proof, it is a safe bet that we'll need to use the rule CP to complete this proof. The use of CP always begins by using a different rule, to begin our hypothetical reasoning.

What rule do we use to initiate the hypothetical reasoning necessary to apply the rule CP$?$

$($Note: Just answer with the abbreviation of the rules name. Do not list any of the other notation normally written in the proof.$)$

$1(1)(($R $->$T$)->$T$)$ A Aim:

$($T $->$ R$)$

Remember $-$ Formatting will be important here! So$,$ enter your wff according to the following conventions:

Make sure you put no spaces between symbols.

Good Not Good!

Wffs: $($PvQ$)($ P v Q $),($P v Q$)$

Premises: $1,2,31,2,3$

Rules: $1,2$MP; $5$&E $1,2$ MP; $5$ &E

Use $\text{'}-\text{'}$ for the dash, a single minus sign.

Use $\text{'}$&$\text{'}$ for the ampersand.

Use $\text{'}$v$\text{'}$ for the wedge, a lower$-$case V$.$

Use $\text{'}->\text{'}$ for the arrow. Copy and paste the arrow from here, if you need it in your answer.

Use $\text{'}\text{'}$ for the contradiction symbol. Copy and paste the upside$-$down T from here.

Use $\text{'}\text{'}$ for the turnstile. Copy and paste it from here, if you need it in your answer.

Use $\text{'}$&I$\text{'},\text{'}$&E$\text{'},\text{'}$vI$\text{'},\text{'}$DN$\text{'},\text{'}$MP$\text{'},\text{'}$MT$\text{'},\text{'}$CP$\text{'},\text{'}$IP$\text{'},\text{'}$I$\text{'}$ for the rules.