Is there any math book (trigonometry) that has exercises with answers?
The standard for math (and science and engineering) topics with loads of worked examples is the Schaum’s Outline series. Not just answers; many solutions include step-by-step explanations. This is in addition to textbook-style exposition of each topic. They also have a solved problems series, which skips the text and has even more problems. There are also some online resources that might help. Many can be found at the Math Forum operated by Drexel University. Here is a page with lots of resources for trig. You can also post a question, and usually get a prompt and helpful reply.
