
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 the vectors $\overrightarrow{a}$ and $\overrightarrow{b}$ with the angle between them being $\theta$, and $\overrightarrow{a}=(-2,1)$, $\overrightarrow{a}+2\overrightarrow{b}=(2,3)$, then the value of $\cos \theta$ is

A) $- \dfrac {3}{5}$

B) $\dfrac {3}{5}$

C) $\dfrac {\sqrt {5}}{5}$

D) $- \dfrac {2\sqrt {5}}{5}$

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