Solve some of the trigonometry identity
1. sin^2(x) + cos^2(x) = 1 (Pythagorean Identity)
2. tan(x) = sin(x) / cos(x)
3. sec^2(x) = 1 / cos^2(x)
4. cot(x) = cos(x) / sin(x)
5. csc^2(x) = 1 / sin^2(x)
6. sin(-x) = -sin(x)
7. cos(-x) = cos(x)
8. sin(π/2 - x) = cos(x)
9. cos(π/2 - x) = sin(x)
10. sin(x + y) = sin(x)cos(y) + cos(x)sin(y)
11. cos(x + y) = cos(x)cos(y) - sin(x)sin(y)
12. sin(2x) = 2sin(x)cos(x)
13. cos(2x) = cos^2(x) - sin^2(x)
14. tan(x + y) = (tan(x) + tan(y)) / (1 - tan(x)tan(y))
15. cot(x + y) = (cot(x)cot(y) - 1) / (cot(y) + cot(x))