Pre Calculus 11 - Trigonometry

Question

P and Q are both points on the unit circle. The standard angle of P is 45° and the standard angle of Q is 150°. Find the length of the chord PQ. Round your answer to 2 decimal places.

Answer 1

Just in case you have not learned the law of cosines yet:

The coordinates of point P are (√2/2,√2/2).

The coordinates of point Q are (-√3/2, 1/2).

These coordinates are based on the relationships between the sides of 45-45 and 30-60 right triangles.

Now use the distance formula to get the distance PQ.

Answer 2

Draw and label a diagram!!

The included angle is 105°

Use the Law of Cosines

PQ² = 1² + 1¹ - 2(1)(1) cos 105°

Can you continue and answer?