few_shots: 
Example 1:
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.

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


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).

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

Example 3:
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 $P$.


Concept/skill: 
Construct a tangent line from a point outside a given circle to the circle.

Answer: 
No. This task does not involve drawing lines that are tangent to circles. The only line that may be drawn is the ray between points P and B.

Now, does the following problem or activity enable students to learn the full intent of the following concept or skill?

shot_info: fl_problem_001894_pos_0

HS_0

im_task_000870_neg_0

HS_1

im_task_001160_neg_0

HS_2
standard_description: Relate counting to addition and subtraction (e.g., by counting on 2 to add 2).
problem_activity: Task
Global Positioning System or GPS devices receive input from satellites and use
this information to locate our position on the planet.   The information received from
each individual satellite gives the distance from the GPS  device to that satellite and the location of the satellite.  The set of points at a fixed distance from a satellite form
a sphere so when the GPS receives its distance from a given satellite, this tells
us that it lies on a particular sphere.  Data from several satellites will
locate the GPS device on the intersection of spheres.  This problem examines different scenarios for intersections of spheres from the point of view of the GPS device: how many
different satellites are needed to locate the GPS device?  Does it matter how
the satellites are configured in space?
Below is a sample picture showing three satellites and their distances, $d_1, d_2, d_3$ from a point on the earth:
[IMG]
The three parts of this problem investigate different positions of the three
satellites pictured above: the goal is to find scenarios where one, two or three of the distances
$d_1$, $d_2$, $d_3$ are (or are not) sufficient to locate the GPS unit.
Give an example of a satellite and GPS location so that the GPS device can determine its location on the earth with input
from this single satellite.  Also give an example when this one signal does not provide
enough information  to designate a location on the earth.
Give  an example of a configuration of two satellites  and the GPS so that the GPS device can determine its location on the earth with input
from the two satellites (but not from either alone).   Also give an example where these two signals do not provide
enough information  to designate a location on the earth.
Give  an example of a configuration of three satellites and the GPS so that  the GPS device can determine its location on the earth with input
from three satellites (but not from any pair of the satellites).   Also give an example where three signals do not provide
enough information  to designate a location on the earth.


aligns: no