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

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: 
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, assess whether the following problem or activity is 'aligned' with the given Common Core standard in Mathematics.

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: Display numerical data in plots on a number line, including dot plots, histograms, and box plots.
problem_activity: Task
2 bottles of water cost $5.00.
Fill in the table that shows the costs for 4, 6, and 8 bottles. Find the cost for a single bottle in each case.
{"table": [{"thead": [{"tr": [{"th": [{"_attributes": {"scope": "col"}, "_value": "Number of bottles"}, {"_attributes": {"scope": "col"}, "_value": "Cost (\\$)"}, {"_attributes": {"scope": "col"}, "_value": "Cost per bottle"}]}]}], "tbody": [{"tr": [{"td": [{"_value": "$$2$$"}, {"_value": "$$5$$"}, {}]}, {"td": [{"_value": "$$4$$"}, {}, {}]}, {"td": [{"_value": "$$6$$"}, {}, {}]}, {"td": [{"_value": "$$8$$"}, {}, {}]}]}]}]}
5 granola bars cost $4.00
Fill in the table that shows the costs for 10, 15, and 20 granola bars. Find the cost for a single granola bar in each case.
{"table": [{"thead": [{"tr": [{"th": [{"_attributes": {"scope": "col"}, "_value": "Number of granola bars"}, {"_attributes": {"scope": "col"}, "_value": "Cost (\\$)"}, {"_attributes": {"scope": "col"}, "_value": "Cost per bar"}]}]}], "tbody": [{"tr": [{"td": [{"_value": "$$5$$"}, {"_value": "$$4$$"}, {}]}, {"td": [{"_value": "$$10$$"}, {}, {}]}, {"td": [{"_value": "$$15$$"}, {}, {}]}, {"td": [{"_value": "$$20$$"}, {}, {}]}]}]}]}
Explain why if you can buy $a$ items for $b$ dollars, or buy $2a$ items for $2b$ dollars, the cost per item is the same in either case.


aligns: no