b$)$

${30}^{-2}=\mathrm{.}601$

a$)x(t)=5cos(100t)$

$\mathrm{.}9cos(2(6-12s))(t)=3cos(30t+40)$

$5cos(7006t+{45}^2)(t)=10cos(700t-10)$

$20cos(0^{15}t)$

$d$

e$)$ What kind of filter is this? $($Lowpass$,$ Highpass, Bandpass, or Bandreject$)?$ for all of them imm confused on how to find phase angle explain in detail please