Chapter 13, Trigonometric Ratios and Functions - 13.3 Evaluate Trigonometric Functions of Any Angle - 13.3 Exercises - Skill Practice - Page 871: 14

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Here, we have $540^{\circ}=540^{\circ}-360=180^{\circ}$ The Trigonometric Identities can be defined as: $\sin 540^{\circ}=\sin 180^{\circ}=0$ $\cos 540^{\circ}=\cos 180^{\circ}=-1$ $\tan 540^{\circ}=\tan 180^{\circ}=0$ $\csc 540^{\circ}=\csc 180^{\circ}=\infty$ or Undefined $\sec 540^{\circ}=\sec 180^{\circ}=-1$ $\cot 540^{\circ}=\cot 180^{\circ}=\infty$ or undefined