It has various calculus-based associations with trigonometry. This site offers a good tutorial based upon the trigonometric function definitions, the values of these functions in Quadrant I, and the trigonometric identities. It provides many practice problems in multiple choice form. An overview is provided for each topic. Each tutorial gives examples and opportunities to try similar problems.
Options are available for instructors to use, including a free quiz.
This site is a well-organized tutorial that covers a wide range of topics. A student can graph trigonometric functions with the 'Plotter' icon. Application problems are under the 'Modules' icon and include finding the true width of strata, cliff erosion, and seismic waves. Exit quizzes are provided, but involves registering on a database. This site is a huge mathematics source.