Sketch the single-sided and double-sided amplitude and phase spectra of  

(a) x₁ (t) = 5 cos (12πt - π/6)

(b) x₂ (t) = 3 sin(12πt) + 4 cos (16πt) 

(c) x₃ (t) = 4 cos (8πt) cos (12πt) 

(d) x₄ (t) = 8 sin (2πt) cos (5πt) 

(e) x₅ (t) = cos (6πt) + 7 cos (30πt) 

(f) x₆ (t) = cos (4πt) + 9 sin (21πt)

(g) x₇ (t) = 2 cos (4πt) + cos (6πt) + 6 sin (17πt)