Topic explanation

Standard explanation

Write 'or', not 'and', for outside roots. 'And' would be the empty overlap of x<-1 and x>3. That word is an exam trap.

Key points

• or = union
• closed includes the root
• U for two pieces
• keep the ideas separate
• Two Rays: Write 'or', not 'and', for outside roots. 'And' would be the empty overlap of x<-1 and x>3. That wor
• WHAT — TWO RAYS: Write 'or', not 'and', for outside roots. 'And' would be the empty overlap of x<-1 and x>3. That wor
• HOW — Use the idea: Identify what is given, select this topic's rule or evidence, apply it one step at a time, and check
• CORE UNDERSTANDING: Write 'or', not 'and', for outside roots. 'And' would be the empty overlap of x<-1 and x>3. That wor

Labelled diagram