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


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

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, assess whether the following problem or activity is 'aligned' with the given Common Core standard in Mathematics.

shot_info: fl_problem_001894_pos_0

HS_0
standard_description: Use geometric shapes, their measures, and their properties to describe objects (e.g., modeling a tree trunk or a human torso as a cylinder).
problem_activity: Task
Milong and her friends are at the beach looking out onto the ocean on a clear day and they wonder how far away the horizon is.
About how far can Milong see out on the ocean?
If
Milong climbs up onto a lifeguard tower, how far is the horizon in Milong's view?
Mount Shishaldin lies on a narrow peninsula in Alaska  and is pictured here:
[IMG]
If Milong were to stand atop Mount Shishaldin and look out over the ocean, how far would the horizon be?
Based on the answers to the questions above,
is the distance of Milong's visual  horizon proportional to her elevation above the surface of the earth?  Explain.


aligns: yes