This question is related to a similar question I asked before but this time the equation has changed. Maxima and minima of sinusoidal function of harmonics
The equation to which i am trying to find a solution is $$f(t)=\ a1\cdot sin(5t)+\ a2\cdot sin(7t)+\ a3\cdot sin(9t)+\ a4\cdot sin(11t)+\ a5\cdot sin(13t).$$
EDIT: I want to find the maxima and minima of the equation mentioned above. Is it possible to find a solution analytically only, without using computation or numerical methods?