
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
A line is parameterized by
\[\begin{pmatrix} x \\ y \end{pmatrix} = \begin{pmatrix} 1 \\ -3 \end{pmatrix} + s \begin{pmatrix} -2 \\ 5 \end{pmatrix}\] 
and another line is given by 
\[\begin{pmatrix} x \\ y \end{pmatrix} = \begin{pmatrix} 4 \\ 1 \end{pmatrix} + v \begin{pmatrix} 6 \\ -1 \end{pmatrix}\].
Find the cosine of the acute angle $\phi$ formed by these two lines.

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