title: maxima multiple trigonometric equations
body: <p>I'm trying to solve an equation using <strong>maxima 13.04.2</strong> but the answer isn't what I expect.
  Example:</p>
  
  <pre><code>y2=A2*cos(2*pi*f2*t+phase2)  we know A2=.4,f2=6.4951,t=1, trying to find **phase2** 
  y2=.4*cos(2*pi*6.4951+phase2)
  </code></pre>
  
  <p>I tried to solve the <strong>y2 equation for phase2</strong> in maxima but it got rid of the cos function</p>
  
  <pre><code>kill(all);
  A:A; phase:phase; solve(A*cos(2*pi*f*t+phase)=0,phase);
  </code></pre>
  
  <p>The answer that came back was</p>
  
  <p><img src="https://i.imgur.com/Bk1gdOal.jpg" alt="strange answer"></p>
  
  <p>I thought something like this was suppose to come back</p>
  
  <pre><code>y2 = A2×cos(2πf2t + φ2) ⇒
  
  y2/A2 = cos(2πf2t + φ2) ⇒
  
  arccos(y2/A2) = 2πf2t + φ2 ⇒
  
  arccos(y2/A2) - 2πf2t = φ2
  </code></pre>
  
  <p>so I could then plug in the vales
  <strong>A2 = 0.4, f2 = 6.4951, t = 1 and get the phase</strong></p>
  
  <p>Any ideas how to get maxima to get the correct format?
  PS: Yes I know I can do it by hand but I have thousands of equations like this and I plan on using octave arrays to call maxima to solve them and bring the answers back into octave.</p>