standard_description: Understand that patterns of association can also be seen in bivariate categorical data by displaying frequencies and relative frequencies in a two-way table. Construct and interpret a two-way table summarizing data on two categorical variables collected from the same subjects. Use relative frequencies calculated for rows or columns to describe possible association between the two variables. For example, collect data from students in your class on whether or not they have a curfew on school nights and whether or not they have assigned chores at home. Is there evidence that those who have a curfew also tend to have chores?
problem_activity: Problem 1
Prove the cofunction identity of:
$${\mathrm{cos}\left({\pi\over2}-x\right)=\mathrm{sin}x}$$
Using the sum or difference formula.
Problem 2
Solve:
$${\mathrm{sin}\left(x+{\pi\over4}\right)+1=\mathrm{sin}\left({\pi\over4}-x\right)}$$
for
$${0 \leq x \leq 2\pi}$$
.


aligns: no