Find the fundamental periods of the following signals:
(a) x₁(t)=10cos(5πt)
(b) x₂(t)=10cos(5πt)+2sin(7πt)
(c) x₃(t)=10cos(5πt)+2sin(7πt)+3cos(6.5πt)
(d) x₄(t)=exp(j6πt)
(e) x₅(t)=exp(j6πt)+exp(−j6πt)
(f) x₆(t)=exp(j6πt)+exp(j7πt)