
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Given $sinα=-\frac{2}{3}$, $α∈({π,\frac{{3π}}{2}})$, $cos\frac{β}{2}=-\frac{{\sqrt{14}}}{4}$, $β∈({\frac{{3π}}{2},2π})$.  
$(Ⅰ)$ Find the values of $\sin \beta$ and $\cos \beta$;  
$(Ⅱ)$ Find the value of $\sin \left(\beta -\alpha \right)$.

Present the answer in LaTex format: \boxed{Your answer}
user