
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
The correct statement(s) among the following is/are \_\_\_\_\_\_\_\_．

$①$ The locus of a moving point $M$ whose distance ratio to two fixed points $A$ and $B$ is a constant $λ (λ > 0, λ ≠ 1)$ is a circle;

$②$ The eccentricity of the ellipse $\frac{{x}^{2}}{{a}^{2}}+\frac{{y}^{2}}{{b}^{2}}=1 (a > b > 0)$ is $\frac{\sqrt{2}}{2}$, hence $b=c$;

$③$ The distance from the focus to the asymptote of the hyperbola $\frac{{x}^{2}}{{a}^{2}}-\frac{{y}^{2}}{{b}^{2}}=1 (a > 0, b > 0)$ is $a$;

$④$ The eccentricity of the hyperbola $\frac{{x}^{2}}{{a}^{2}}-\frac{{y}^{2}}{{b}^{2}}=1 (a > b > 0)$ whose asymptote has an inclination angle of $θ$ is $\frac{1}{\cos θ}$.

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