An interesting trigonometric simplification

[fredrik-johansson]

v = cos(acos(sqrt(2) - sqrt(3))/3)
assert 1 - 90*v**2 + 321*v**4 - 592*v**6 + 864*v**8 - 768*v**10 + 256*v**12 == 0

This equality test interestingly enough works; however, v is not simplified to an algebraic number automatically. This ought to be done.