Hello,

e ^(ρ.cosθ) << this is a real number

cos(ρ sinθ – nθ) << as mentioned this is the real part of cos(ρ sinθ – nθ) + i sin (ρ sinθ – nθ)

But we know that cos(ρ sinθ – nθ) + i sin (ρ sinθ – nθ) is equal to e^(ρ sinθ – nθ) !

Can you simplify the thing ?