If eiθ=cosθ+isinθ, then the value of ∣∣∣∣∣1e−iπ/3e−iπ/4eiπ/31e−i2π/3eiπ/4ei2π/31∣∣∣∣∣is

[c] Expanding by Sarrus rule, ∣∣∣∣∣1e−iπ/3e−iπ/4eiπ/31e−i2π/3eiπ/4ei2π/31∣∣∣∣∣=1+eiπ/3×ei2π/3×e−iπ/4+ e−iπ/3×e−i2π/3×e−iπ/4−(ei2π/4×e−iπ/4+e−iπ/3×                         e−iπ/3+e−iπ/3×e−i2π/3) =1+ei3π/4+e−i3π/4−(1+1+1) =−2+2cos(3π/4)=−2−2√