Question

What is the rule for a counterclockwise rotation about the origin of 210°

Answer 1

(x, y) ⇒ (-x√3/2 +y/2, -x/2 -y√3/2)

Explanation:

The rule for CCW rotation through an angle α is ...

(x, y) ⇒ (x·cos(α) -y·sin(α), x·sin(α) +y·cos(α))

So, for α = 210°, the rule becomes ...

(x, y) ⇒ (-x√3/2 +y/2, -x/2 -y√3/2)