17. 如圖(二)所示電路,若 i(t) = 20 cos (200t - 45˚),求之值為何? (A) 20 cos (200t-45˚) V (B) 20 cos (200t + 45˚) V (C) 40 cos (200t-45˚) V (D) 40 cos (200t + 45˚) V