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: Relate counting to addition and subtraction (e.g., by counting on 2 to add 2).
problem_activity: Narrative
The purpose of this activity is for students to choose from activities focusing on two-digit numbers. Students are introduced to stage 6 of the Five in a Row center. Then students choose between that center or others previously introduced.
Students choose from any stage of previously introduced centers.
Five in a Row
Get Your Numbers in Order
Grab and Count
Required Materials
Materials to Gather
Materials from previous centers
Paper clips
Two-color counters
Materials to Copy
Five in a Row Addition and Subtraction Stage 6 Gameboard
Required Preparation
Gather materials from previous centers:
Five in a Row, Stages 1-6
Get Your Numbers in Order, Stage 1
Grab and Count, Stage 2
Launch
Groups of 2
“Now you will choose from other centers we have already learned. One of the choices is to play Five in a Row with a new gameboard. On this gameboard you will add 2 two-digit numbers that make a new ten.”
Display the center choices in the student book.
“Think about what you would like to do first.”
30 seconds: quiet think time
Activity
8 minutes: center work time
“Choose what you would like to do next.”
8 minutes: center work time
Student Facing
Choose a center.
Five in a Row
[IMG]
Get Your Numbers in Order
[IMG]
Grab and Count
[IMG]
Activity Synthesis
“What did the centers you chose help you work on?”


aligns: yes