standard_description: Construct the inscribed and circumscribed circles of a triangle, and prove properties of angles for a quadrilateral inscribed in a circle.
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