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:
[IMG]
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

HS_1

im_task_001160_pos_0

HS_2
standard_description: Solve word problems that call for addition of three whole numbers whose sum is less than or equal to 20, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.
problem_activity: Narrative
The purpose of this activity is for students to write equations to represent the data they collected in Unit 1. Students can write any equation that makes sense to them.
This activity is intended to follow the last lesson of Unit 1. If that lesson was not completed, students can use sample data from the blackline master to complete this task.
When students use real-world data that they collect and determine ways of fitting their data into an existing mathematical model—put-together problems with unknowns in various positions—they model with mathematics (MP4).
To make this activity more challenging, students can share only their equation. Then their partner looks at the data and determines what story the writer intended to represent.
Required Materials
Materials to Gather
Materials from a previous lesson
Materials to Copy
Revisit Data
Required Preparation
Gather survey data from the last lesson in the previous unit, Animals in the Jungle.
Launch
Groups of 2
Give each group the data or posters from the previous unit or the sample data from the blackline master.
“Take a look at the work you did a few weeks ago. Review what you investigated and what you discovered.”
1 minute: quiet think time
“Discuss with a partner.”
2 minutes: partner discussion
Activity
Read the task statement.
5 minutes: independent work time
“Take turns telling your partner a story problem that matches the equations you wrote.”
5 minutes: partner discussion
Student Facing
Write at least 3 equations that match your survey data.
Student Response
Teachers with a valid work email address can
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for free access to Student Response.
Activity Synthesis
“What did you notice about making up a story problem for your equation? Were some easier than others? Why were they easier?”


aligns: yes