- #1

mathdad

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1. cos 4π/3

A. We are told to graph cos 4π/3. We are in Quadrant 3.

B. Find the reference number r.

r = 3π/2 - 4π/3

r = π/6

C. Evaluate r.

cos π/6 = -sqrt{3}/2

Book's answer for r is -1/2.

2. sec 4π/3

A. We are told to graph sec 4π/3.

We are in Quadrant 3.

B. Find the reference number r.

r = 3π/2 - 4π/3

r = π/6

C. Evaluate r.

sec π/6 = -2sqrt{3}/3.

Book's answer for r is -2.