如何获得用户友好的三角函数值？
我正在开发一个安卓应用程序。用于数学计算。我有一些按钮，如 sin、cos、tan，它们应该显示它们各自的三角值，因为我正在使用 java.lang.Math 类的相应方法并且工作正常。但经过一些测试后我发现，它显示了一些结果，如下所示
sin(90)=0.89399........ //I want it to show 1
cos(90)=-0.44807........ //I want it to show 0
tan(90)=-1.995200...... //I want it to show Infinity as sin(90)/cos(90)=1/0=Infinity
，就像上面的例子一样，有很多显示这样的结果。我应该怎么做才能得到上面提到的结果。请帮我。
I am developing an android app. for mathematical calculations. There I have some buttons like sin,cos,tan which should show their respective trigonometric values, for that I am using corresponding methods of java.lang.Math class and that works fine. But after some tests I came to know that, it shows some results as follows
sin(90)=0.89399........ //I want it to show 1
cos(90)=-0.44807........ //I want it to show 0
tan(90)=-1.995200...... //I want it to show Infinity as sin(90)/cos(90)=1/0=Infinity
Like the above examples there are many which show results like this. What should I do this for getting the results as mentioned above. Please help me.
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（4）
你的问题是java使用弧度而不是度数一个>。您必须先将角度转换为弧度。
Your problem is that java uses radians and not degrees. You have to convert the angle to rad first.
Javadoc 到救援：
（强调我的）
首先将你的角度转换成弧度。 360 度 = 2 * 圆周率。
Javadoc to the rescue:
(emphasis mine)
Convert your degrees into radians first. 360 degrees = 2 * pi.
首先，三角函数不适用于您正在使用的度数。您必须发送 3.1415926/2 而不是 90。在这种情况下，
sin将更接近 1，cos 更接近 0。但数字仍然是浮点数。如果您想对它们进行舍入以进行演示，请使用
DecimalFormat类或String.format()方法。First, trigonometric functions do not work with degrees that you are using. You have to send 3.1415926/2 instead of 90. In this case
sinwill be much closer to 1 and cos much closer to 0.But the numbers will still be floating point. If you want to round them for presentation use
DecimalFormatclass orString.format()method.看一下 数学.round()。
另外，我上次检查时，每当你除以 0 时，你都不会得到无穷大。除以 0 是未定义的。
另外，Java 使用弧度来表示三角函数，因此请确保您使用的是弧度而不是角度或梯度。
Take a look at Math.round().
Also, last time I checked, whenever you devide by 0 you do not get infinity. Division by 0 is undefined.
Also, Java uses radians for trigonometric functions, so be sure you are using radians and not degrees or gradians.