
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 a point $P$ on the circle $x^{2}+y^{2}=18$, let $PQ$ be perpendicular to the x-axis at point $Q$. If a moving point $M$ satisfies $\overrightarrow{OM}= \frac {1}{3} \overrightarrow{OP}+ \frac {2}{3} \overrightarrow{OQ}$,  

(Ⅰ) Find the equation of the trajectory $C$ of the moving point $M$;  

(Ⅱ) The line passing through point $E(-4,0)$ with an equation $x=my-4\ (m\neq 0)$ intersects the curve $C$ at points $A$ and $B$, and the perpendicular bisector of segment $AB$ intersects the x-axis at point $D$. Find the value of $\frac {|DE|}{|AB|}$.

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