title: law of cos in C++ visual studio
body: <p>I could not figure out the inverse cosine part to make it work. Or perhaps I made more mistakes than that.</p>
  
  <p>using namespace std;</p>
  
  <pre><code>int main()
  
  {
  
      double a,b,c,angle,acos;
  
      cout &lt;&lt; "Enter the value of a"&lt;&lt;endl;
      cin &gt;&gt;a;
  
      cout &lt;&lt; " Enter the value of b "&lt;&lt;endl;
      cin &gt;&gt; b;
  
      cout &lt;&lt; "Enter the value of c " &lt;&lt;endl;
      cin &gt;&gt; c;
  
      angle = acos*(-0.6481) * ((a*a+b*b-c*c)/2*a*b);
  
      cout &lt;&lt; "The angle of cos is " &lt;&lt;angle&lt;&lt; endl;
  
      system ("pause");
  
  }
  </code></pre>