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: Recognize and draw shapes having specified attributes, such as a given number of angles or a given number of equal faces. (Sizes are compared directly or visually, not compared by measuring.) Identify triangles, quadrilaterals, pentagons, hexagons, and cubes.
problem_activity: Narrative
The purpose of this activity is for students to learn stage 2 of the Estimate and Measure center. Students estimate and measure the length of objects. This stage includes centimeters, inches, and feet. Students should only measure in centimeters at this point in the unit. In this activity, students also find the difference between their estimate and their measurement for extra practice.
Required Materials
Materials to Gather
Metersticks
Objects of various lengths
Rulers (centimeters)
Materials to Copy
Estimate and Measure Stage 2 Recording Sheet
Required Preparation
Gather or identify objects of various lengths (pencils, markers, books, glue, scissors, shoe, tape dispenser, side of desk, length of bulletin board).
Launch
Groups of 2
Give students access to centimeter rulers and meter sticks.
Give each student a recording sheet.
“We are going to learn a new center called Estimate and Measure. Today we are going to estimate and measure the length of different objects.”
“First you and your partner will decide on an object in the room to measure. Then you will decide what tool you will use to measure the object.”
Choose an object to measure and hold it up for students to see.
“What tool would you use to measure this object?”
“Before measuring the object, you and your partner will both estimate the length of the object using the unit you chose. Your estimates do not have to be the same. Record your estimate.”
Demonstrate estimating the length of your object and recording it on the recording sheet.
“Now work with your partner to measure the object and record the actual measurement.”
Demonstrate measuring the object, thinking aloud as you line up the endpoints and use the number on the tool to determine the length.
Record the actual measurement on the recording sheet.
“If you have time: Once you have estimated and measured the object, find the difference between your estimate and the actual length.”
Demonstrate finding the difference.
“Put your object back and choose another object to measure.”
Activity
10 minutes: partner work time
Activity Synthesis
Display a row of the recording sheet with this information:
Object: notebook
Estimate: 20 cm
Actual Measurement: 31 cm
“How can we find the difference?” (We can add on to 20 until we get to 31. We can subtract 20 from 31.)


aligns: no