few_shots: 
Example:
Concept/skill: 
Prove the addition and subtraction formulas for sine, cosine, and tangent and use them to solve problems.

Problem/activity:
Find the general solution for:
$${\mathrm{cos}\left({\pi\over2}+x\right)=\mathrm{tan}{\pi\over4}}$$


Answer: 
Yes. An initial step when solving for x in this problem requires the use of the addition formula for cosine on the left side of the equation.

Now, determine whether the following problem or activity can enable students to understand the concepts or skills in the provided description.

shot_info: fl_problem_001894_pos_0

HS_0
standard_description: Derive the equation of a parabola given a focus and directrix.
problem_activity: Below is an illustration of an aquarium. There are four possibilities of changes that affect the water level: addition/removal of a rock, insertion/removal of a plug, turn on/off the faucet, use the bucket to add/remove water.
[IMG]
The graph below shows the height of the water in the aquarium over a 17-minute time interval. Write a story from the point of view of someone watching what is going on with the aquarium to produce the given graph.
[IMG]
The graph given above is a simplified version of reality. What simplifying assumptions did we make when we created the graph?


aligns: no