
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 an ellipse $\dfrac {x^{2}}{a^{2}}+ \dfrac {y^{2}}{b^{2}}=1(a > b > 0)$ with two vertices $A(0,b)$ and $C(0,-b)$, and two foci $F_{1}(-c,0)$ and $F_{2}(c,0)(c > 0)$, a line through point $E(3c,0)$ intersects the ellipse at another point $B$, and $F_{1}A\parallel F_{2}B$.  
(Ⅰ) Find the eccentricity of the ellipse;  
(Ⅱ) Suppose there is a point $H(m,n)(m\neq 0)$ on the line $F_{2}B$ that lies on the circumcircle of $\triangle AF_{1}C$, find the value of $\dfrac {n}{m}$.

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