Post-class 04/01

1 files changed, 36 insertions, 0 deletions

diff --git a/1.1.md b/1.1.md
index a04674d..dc949c8 100644
--- a/1.1.md
+++ b/1.1.md
@@ -182,3 +182,39 @@ when `p` is true, `┓p` is false, and vice versa
 - Satisfied when either `p` and `q` are both true or both false
 
 - `p<->q` is "equivalent" to `(p->q)^(q->p)`
+
+---
+
+# Propositional Logic p2
+
+- ex: What operator do we do first in `┓p^q<->r`
+
+## Precedence (order of operations)
+
+1. `┓`
+2. `^`, `∨`, `⊕`
+	- "Exclusive or" (`⊕`) is sometimes referred to as "Ex Or" for short
+	- Need parenthesis to differentiate among these
+3. `->`, `<->`
+	- Need parenthesis to differentiate among these
+	
+`┓p^q<->r` means `(┓p^q)<->r`
+
+- ex: `p^q∨r`
+	- is ambiguous (not sure what to do first) because of lack of parethesis
+
+- ex: Translate the following sentence to logic:
+	- "You can be Draco's friend **only if** you are in Slytherin **or** you eat floating cupcakes"
+	- let `d` = "You can be Draco's friend
+	- let `s` = "You are in Slytherin"
+	- let `c` = "You eat floating cupcakes"
+	- `d->s∨c` or `d->(s∨c)`
+		- Mean the same thing
+
+- Note: "p if q" means `p<-q` (or `q->p`)
+- Note: "p only if q" means `p->q`
+- Note: "p if and only if q" means `p<->q`
+
+---
+
+[1.3 ->](1.3.md)