question: $f$ is a trigonometric function of the form $f(x)=a \cos (b x+c)+d$.
  Below is the graph of $f(x)$. The function has a maximum point at $(-2,-3)$ and a minimum point at $(-2.5,-9)$. Find a formula for $f(x)$. Give an exact expression.
  
query_wo: Please directly answer the question and provide the final value, e.g., 1, 2.5, 300.
  Question: $f$ is a trigonometric function of the form $f(x)=a \cos (b x+c)+d$.
  Below is the graph of $f(x)$. The function has a maximum point at $(-2,-3)$ and a minimum point at $(-2.5,-9)$. Find a formula for $f(x)$. Give an exact expression.
  
query_cot: Please first conduct reasoning, and then answer the question and provide the final value, e.g., 1, 2.5, 300, at the end.
  Question: $f$ is a trigonometric function of the form $f(x)=a \cos (b x+c)+d$.
  Below is the graph of $f(x)$. The function has a maximum point at $(-2,-3)$ and a minimum point at $(-2.5,-9)$. Find a formula for $f(x)$. Give an exact expression.
  
question_for_eval: $f$ is a trigonometric function of the form $f(x)=a \cos (b x+c)+d$.
  Below is the graph of $f(x)$. The function has a maximum point at $(-2,-3)$ and a minimum point at $(-2.5,-9)$. Find a formula for $f(x)$. Give an exact expression.
  