calculus第一题UseDeMoivre'sTheoremwithn=3toexpresscos(3θ)andsin(3θ)intermsofcos(θ)andsin(θ)cos(3θ)\x05=sin(3θ)\x05=第2题FindtheindicatedpowerusingDeMoivre'sTheorem.（1+i)^20

Question

calculus
第一题
Use De Moivre's Theorem with n = 3 to express cos(3θ) and sin(3θ) in terms of cos(θ) and sin(θ)
cos(3θ)\x05 =
sin(3θ)\x05 =
第2题
Find the indicated power using De Moivre's Theorem.
（1+i )^20

Answer 1

sin3x=(e^i3x-e^-i3x)/2i
cos3theta=(e^3x+e^-3x)/2
2^10 * e^(i5n)