chapter - 4 - trigonometric functions chapter - 4 - trigonometric functions - Ex: 4.1 -or- chapter - 4 - trigonometric functions - Ex: 4.2 -or- chapter - 4 - trigonometric functions - Ex: 4.3 -or- chapter - 4 - trigonometric functions - Ex: 4.4 -or- chapter - 4 - trigonometric functions - Ex: 4.5 -or-