Best way to solve equations like that

[fishingspree2]

Im doing a physics equilibrium problem and I need to solve this equation:

900cos(x)+600cos(45+x) = 0

(the angles are in degrees)

What would be the best way to analytically solve this kind of equation? I tried using the sum-difference formulas but it wasn't able to solve for x.

Thank you very much

 

[sachinism]

well the question is essentially only in one variable x

so instead of adding them what u do is , expland the cos(45+x) term

then put cosx=t and sinx whill be sqrt(1-t^2)

and solve the q in t

and then look at the permissible values of t

since t belongs to [-1,1]