trigonometry

I found Playing an arbitrary tone with Android to be helpful when I was generating a frequency tone. Now I want the frequency to change while the tone is playing. I modified the genTone to be similar to this: private void genTone(double startFreq, double endFreq, int dur) { int numSamples = dur * sampleRate; sample = new double[numSamples]; double currentFreq = 0, numerator; for (int i = 0; i < numSamples; ++i) { numerator = (double) i / (double) numSamples; currentFreq = startFreq + (numerator * (endFreq - startFreq)); if ((i % 1000) == 0) { Log.e("Current Freq:", String.format("Freq is: %f

In the above image, I have three points (x1,y1) (x2,y2) (x3,y3) . I know the values of x1,y1 and x2,y2 .I know the euclidean distances of (x1,y1)->(x3,y3) and (x2,y2)->(x3,y3) . Having these information how can I find the (x3,y3) ? I expect anything like a code snippet or the logic will be useful... I have tried to solve this using the circle equations but I don't know how to proceed. We can solve this using a bit of trigonometry: Cosine theorem (phi is the inner angle at the first point): d3^2 = d1^2 + d2^2 - 2 d1 d2 cos phi cos phi = (d1^2 + d2^2 - d3^2) / (2 d1 d2) For a given cosine, we

OK, I know this sounds like it should be asked on math.stackoverflow.com, but this is embarrassingly simple maths that I've forgotten from high-school, rather than advanced post-graduate stuff! I'm doing some graphics programming, and I have a triangle. Incidentally, two of this triangle's sides are equal, but I'm not sure if that's relevant. I have the coordinates of two of the corners (vertices), but not the third (these coordinates are pixels on the screen, in case that's relevant). I know the lengths of all three sides. How do I determine the coordinates of the unknown vertex? for oblique

Can anyone point me to a good example of Atan2 defined in C# (or something vaguely close to C#) that doesn't use any internal math methods? This is on .NET Microframework, so there is no such thing as an internal math library. I have already defined Sin()/Cos(), but I am having a lot of trouble with Atain2. There are a few scatter shot math libraries in NETMF, but I have found them all to be flawed or broken. One of the major ones didn't even define PI correctly! An implementation should be quite straight forward starting with the definition on Wikipedia/atan2 and then using the infinite

i wrote a program to arrange points on a graph in clockwise manner from 12 o'clock such that, a vector containing these points is sorted in that order. I am using atan2 to get the angle from 12 o'clock and then making adjustments based on the quadrant. i am trying to figure out where the bug is coming from as it is not ordering them correctly. So given 4 random points like those in the photo, it should order then in the containing vector as P1,P2,P3,P4 Here is my code: //sort_points.cpp #include <iostream> #include <math.h> #include <algorithm> #include <vector> using namespace std; class

I know how to find out angle between 2 vectors, but it always gives me internal angle, but I want it to give me always the angle in anticlockwise direction, even if it is greater then 180. I'm using C++ but it is not really important because I need to get the theory. This is what I am using now You're looking for the atan2(y,x) function ( http://en.wikipedia.org/wiki/Atan2 ). If you give it the two components of a 2D vector, it will give you the angle of the vector from the x axis, in the counter-clockwise direction. To solve your specific problem try: atan2(v_y, v_x) - atan2(u_y, u_x) Then