sin2A + cos2A
In Geometry, you learn about triangles. In Trigonometry you learn even more about triangles.
conclusion
Learn the subject!
It depends. Between 9th to 12th.
Trigonometry isn't required to learn calculus, but it does help you to understand some of the concepts. Geometry, however, is usually required before taking a course in trigonometry.
SOH KAH TOA
If they put their mind to it, it is not difficult.
Trigonometry is engineering math, but If you are going to study something in physics, or science, (basically this is "applied science"), you will need lots of calculus. calculus appears a lot in "Stargate".
YES! If you can't do algebra, you won't last ten seconds in trigonometry. It basically is algebra, just using equations within equations.
Pay attention in class. That is the simplest way.
Math gets much better once you get past trigonometry into Calculus. You learn trig to help with many things later in life. (Believe me you will use it). Calculus can be used to describe ANYTHING, and is so powerful that you will be amazed when you learn it. Things that you thought you could never understand because they were too difficult suddenly you can. So just keep plugging away at trigonometry and I promise it will get better and they will be the most important things you learn in school.
Aryabhata is the author of, Aryabhatiya, his major work, which is a compendium of mathematics and astronomy and extensively referred to in the Indian mathematical literature. The mathematical part of the Aryabhatiya covers arithmetic, algebra, plane trigonometry and spherical trigonometry. It also contains continued fractions, quadratic equations, sums of power series and a table of sines.