trigonometry

问题 From my understanding, the atan2() function exists in programming languages because atan() itself cannot always determine the correct theta since the output is restricted to -pi/2 to pi/2. If this is the case, then the same problem applies to both asin() and acos() , both of whom also have restricted ranges, so then why are there no asin2() and acos2() functions? 回答1: First off, note that the syntaxes of the two arctan functions are atan(y/x) and atan2(y, x) . This distinction is important,

问题 This question already has answers here : Draw perpendicular line of fixed length at a point of another line (3 answers) Closed 21 days ago . I'm trying to draw a line segment orthogonal/perpendicular to the current line segment from the terminal point for a given length, here's an illustration to help better explain the problem: Given the line a coordinates and an arbitrary length , I'd like to find the coordinates for line segment b and (x3,y3) . Appreciate any help. UPDATE: Found my

问题 This question already has answers here : Draw perpendicular line of fixed length at a point of another line (3 answers) Closed 21 days ago . I'm trying to draw a line segment orthogonal/perpendicular to the current line segment from the terminal point for a given length, here's an illustration to help better explain the problem: Given the line a coordinates and an arbitrary length , I'd like to find the coordinates for line segment b and (x3,y3) . Appreciate any help. UPDATE: Found my

问题 I need to draw a circle with 4 sectors. I'm trying to draw a sector like this: <path d="M200, 200, l 100,-100 a180,180 0 0,0 -127.27,127.27 z"/> I got the -127.27, 127.27 from the equations: x=cos(angle) * radius y=sin(angle) * radius My angle is 135, and my radius is 180. Here's a codepen of what i get: http://codepen.io/anon/pen/QjKgdY The blue one is the one I'm talking about here, the black one is me trying different numbers. Why am i not getting a proper 1/4 of a circle? What am i

问题 I need to draw a circle with 4 sectors. I'm trying to draw a sector like this: <path d="M200, 200, l 100,-100 a180,180 0 0,0 -127.27,127.27 z"/> I got the -127.27, 127.27 from the equations: x=cos(angle) * radius y=sin(angle) * radius My angle is 135, and my radius is 180. Here's a codepen of what i get: http://codepen.io/anon/pen/QjKgdY The blue one is the one I'm talking about here, the black one is me trying different numbers. Why am i not getting a proper 1/4 of a circle? What am i

问题 I'm working on a problem that has to do with calculating angles of refraction and what not. However, it seems that I'm unable to use the numpy.sin() function in degrees. I have tried to use numpy.degrees() and numpy.rad2deg(). numpy.sin(90) numpy.degrees(numpy.sin(90)) Both return ~ 0.894 and ~ 51.2 respectively. Thanks for your help. 回答1: You don't want to convert to degrees, because you already have your number (90) in degrees. You need to convert 90 from degrees to radians, and you need to

问题 I'm working on a problem that has to do with calculating angles of refraction and what not. However, it seems that I'm unable to use the numpy.sin() function in degrees. I have tried to use numpy.degrees() and numpy.rad2deg(). numpy.sin(90) numpy.degrees(numpy.sin(90)) Both return ~ 0.894 and ~ 51.2 respectively. Thanks for your help. 回答1: You don't want to convert to degrees, because you already have your number (90) in degrees. You need to convert 90 from degrees to radians, and you need to

问题 I am trying to write a function that will randomly return an (x,y) co-ordinates around a given circumference so if I have a point that's at (0,0) (being the center of the div) how can I write a function that randomly places other entities that appear among the outer edge of a circle. All I need is the equation i know it has something to do with getting the distance from the center to the circumference edge just no idea how to calculate it and randomize it so it looks good. 回答1: Just get a

来源： https://stackoverflow.com/questions/64580873/why-are-my-bullets-travelling-at-a-90-degree-angle-from-the-mouse

来源： https://stackoverflow.com/questions/64580873/why-are-my-bullets-travelling-at-a-90-degree-angle-from-the-mouse