few_shots: 
Example:
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.

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
standard_description: Understand that rewriting an expression in different forms in a problem context can shed light on the problem and how the quantities in it are related. For example, a + 0.05a = 1.05a means that “increase by 5%” is the same as “multiply by 1.05.”
problem_activity: Problem 1
Four expressions are shown in the chart below. For each one, write all the ways to read the expressions that you can think of.
| **             $${x+2}$$            ** |                 $${x-2}$$                 |
|----------------------------------------|-------------------------------------------|
|                                        |                                           |
|                $${2x}$$                | **             $${x\div2}$$            ** |
|                                        |                                           |
Problem 2
Two tape diagrams are shown below. The shading indicates subtraction.
[IMG]
Statements a–h below can be used to describe either Diagram 1 or Diagram 2. Match each statement to one of the diagrams.
a.   The difference of
$$4$$
and
$$m$$
b.   The difference of
$$m$$
and
$$4$$
c.
$$4$$
less than
$$m$$
d.
$$m$$
less than
$$4$$
e.
$$4$$
less
$$m$$
f.
$$m$$
less
$$4$$
g.   Subtract
$$4$$
from
$$m$$
h.   Subtract
$$m$$
from
$$4$$
Problem 3
For each verbal statement, write the algebraic expression it describes.
a.   The sum of
$$e$$
and
$$f$$
subtracted from
$$g$$
b.
$$g$$
less than the sum of
$$e$$
and
$$f$$
c.
$$g$$
more than twice
$$f$$


aligns: no