few_shots: 
Example 1:
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.

Example 2:
Concept/skill: 
Understand that the graph of an equation in two variables is the set of all its solutions plotted in the coordinate plane, often forming a curve (which could be a line).

Problem/activity:
Task
Solve the quadratic equation
$$ x^2 = (2x - 9)^2 $$
using as many different methods as possible.


Answer: 
No. This task does not involve an equation in two variables. There is only one variable, x.

Example 3:
Concept/skill: 
Make formal geometric constructions with a variety of tools and methods (compass and straightedge, string, reflective devices, paper folding, dynamic geometric software, etc.). Copying a segment; copying an angle; bisecting a segment; bisecting an angle; constructing perpendicular lines, including the perpendicular bisector of a line segment; and constructing a line parallel to a given line through a point not on the line.

Problem/activity:
Task
Suppose $A$ is an angle with vertex $P$, as pictured below:
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Draw a circle with center $P$ and with  radius $r \gt 0$.  Explain why the circle
meets each ray of angle $A$ in a single point.  Label these points $Q$ and $R$ respectively.
Draw circles with centers $Q$ and $R$ respectively and radius $r$.  These circles meet at $P$ and a second point to be labelled $B$.
Show that ray $\overrightarrow{PB}$  bisects angle $P$.


Answer: 
Yes. This task asks students to draw a ray that bisects an angle. The act of drawing circles and rays may involve compass and straightedge or dynamic geometric software.

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

im_task_000870_neg_0

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im_task_001160_pos_0

HS_2
standard_description: Given a rectangle, parallelogram, trapezoid, or regular polygon, describe the rotations and reflections that carry it onto itself.
problem_activity: Activity
In this activity students use trigonometry to calculate the measure of an angle when given two sides of a right triangle. Then they apply a method of their choosing to calculate other side lengths and angle measures in the triangle.
Monitor for students who use:
the Pythagorean Theorem
multiple trigonometric equations
the Triangle Angle Sum Theorem
Launch
“Don’t forget to calculate 3 measurements per triangle.”
Students need not complete all the problems before the discussion.
Engagement: Provide Access by Recruiting Interest.
Leverage choice around perceived challenge. Invite students to select 2 of the 3 questions to complete. Chunking this task into more manageable parts may also support students who benefit from additional processing time.
Supports accessibility for: Organization; Attention; Social-emotional skills
Student Facing
Find all missing side and angle measures.
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Student Response
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Activity Synthesis
Tell students there are at least 3 different methods for solving these problems:
Pythagorean Theorem
multiple trigonometric equations
the Triangle Angle Sum Theorem
Invite students to rank the methods in order of most to least preferred and tell them to be prepared to share their reasoning. After 1 minute of quiet think time ask a few students to share. Tell the class that there is no one best method; personal preference and the specific problem both influence your choices.
Speaking: MLR8 Discussion Supports.
To support students in producing statements about the methods they preferred for solving the problems, provide sentence frames for students to use when they share. For example, “I prefer _____ because _____,” or  “_____ was better because _____.”
Design Principle(s): Support sense-making


aligns: no