Missing most of grade 12 to the MUN trip, Isaac and David remained and attacked an extension problem related to the current topic: trigonometric identities.
Ask them to reproduce the proof for each of these claims, using a rotated rectangle:
Sin(θ+α) = sin(θ)cos(α) + cos(θ)sin(α)
Cos(θ+α) = cos(θ)cos(α) – sin(θ)sin(α)
