How to find cosine inverse in C programming
How to find which triangle is obtuse , acute or right angled. So by cosine rule if a,b,c are sides of triangle and A,B,C are angles of triangle then
cosA = (b^2+c^2-a^2)/2bc . Hence A = cos-1(b^2+c^2-a^2)/2bc.
hence how to find cosine inverse in C programming ?