In short, if you are looking for the coordinates of a point located on a circle of radius 1 at a given counter-clockwise angle from the right-most point of the circle, its y coordinate will be given by the sine of this angle, and its x coordinate will be given by the cosine of this angle.
If your circle has a radius of something other than 1, you must multiply by that radius, hence the *someotherNumber in your equations.
1) What is the opposite and what exactly is the hypotenuse in the above lines?
First of all, someNumber is going to represent an angle measured in radians. The cos and sin values represent the sine and cosine of that angle. Usually, we think of a triangle with hypotenuse 1, so that cosine and sine become like (x,y) co-ordinates in a plane.
2) What does it actually do?
Although you may think of sine and cosine as something you would need to know the length of three sides of a triangle to calculate, there are methods to calculate them using ordinary arithmetic (addition, subtraction, multiplication, division). When the code is executed, some such method is likely used to perform the calculation. Here is one of the most famous examples: http://en.wikipedia.org/wiki/Taylor_series
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我建议您阅读有关单位圈的维基百科条目。
简而言之，如果您要查找位于半径为 1 的圆上、与圆的最右边点以给定逆时针角度的点的坐标，则其 y 坐标将由该角度的正弦给出，它的 x 坐标将由该角度的余弦给出。
如果圆的半径不是 1，则必须乘以该半径，因此方程中为
*someotherNumber。I recommend you read the Wikipedia entry on the unit circle.
In short, if you are looking for the coordinates of a point located on a circle of radius 1 at a given counter-clockwise angle from the right-most point of the circle, its y coordinate will be given by the sine of this angle, and its x coordinate will be given by the cosine of this angle.
If your circle has a radius of something other than 1, you must multiply by that radius, hence the
*someotherNumberin your equations.http://cda.morris.umn.edu/~mcquarrb/ Precalculus/Animations/SineCosineAnim.html
正弦和余弦函数通常用于计算已知距离和角度的点的坐标。
http://cda.morris.umn.edu/~mcquarrb/Precalculus/Animations/SineCosineAnim.html
The sine and cosine functions are often used to calculate a coordinate for a point of which you know the distance and the angle.
你问了两个问题：
1）上面几行的相反的斜边是什么？
首先，
someNumber将表示以弧度测量的角度。cos和sin值表示该角度的正弦和余弦。通常，我们认为斜边为 1 的三角形，因此余弦和正弦就像平面中的 (x,y) 坐标。2）它实际上有什么作用？
尽管您可能认为正弦和余弦需要知道三角形三边的长度才能计算，但有一些方法可以使用普通算术（加法、减法、乘法、除法）来计算它们。当代码执行时，可能会使用一些这样的方法来执行计算。这是最著名的例子之一：http://en.wikipedia.org/wiki/Taylor_series
You've asked two questions:
1) What is the opposite and what exactly is the hypotenuse in the above lines?
First of all,
someNumberis going to represent an angle measured in radians. Thecosandsinvalues represent the sine and cosine of that angle. Usually, we think of a triangle with hypotenuse 1, so that cosine and sine become like (x,y) co-ordinates in a plane.2) What does it actually do?
Although you may think of sine and cosine as something you would need to know the length of three sides of a triangle to calculate, there are methods to calculate them using ordinary arithmetic (addition, subtraction, multiplication, division). When the code is executed, some such method is likely used to perform the calculation. Here is one of the most famous examples: http://en.wikipedia.org/wiki/Taylor_series
正弦和余弦函数已推广到所有实数值。请参阅：
http://en.wikipedia.org/wiki/Trigonometric_functions#Unit-circle_definitions< /a>
这是这些调用计算的结果。
The sine and cosine functions have been generalised for all real values. See:
http://en.wikipedia.org/wiki/Trigonometric_functions#Unit-circle_definitions
This is what is computed by the those calls.