
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 function $y = \cos x - \sin x$, translate it graphically to the right by $φ$ ($φ > 0$) units, and then stretch the horizontal coordinates of each point on the obtained graph by a factor of $a$, resulting in the graph of $y = \cos 2x + \sin 2x$. Determine the possible values of $φ$ and $a$.

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