Did you learn trigonometric function in the second volume or the first volume of the ninth grade?
The first volume of the ninth grade. According to the mathematics textbook of the first volume of the ninth grade, trigonometric function is the content of the first volume of the ninth grade. This paper mainly introduces the acute angle trigonometric function and its simple calculation. Then the second volume of Senior One (the second volume of Grade 10) introduces trigonometric functions at any angle and provides a lot of formulas of trigonometric functions and sine and cosine theorems.