Euler's Theorem
Complex Numbers of Class 11
Euler's Theorem
cosθ + i sinθ = eiθ
This result can be obtained by simply using the expansion of cos θ and sin θ that is
cos θ + i sin θ = 
+ i 
= 1 + iθ + 
+ …… = eiθ and thus cos θ − i sin θ = e-iθ
cosθ + i sinθ = eiθ
This result can be obtained by simply using the expansion of cos θ and sin θ that is
cos θ + i sin θ = + i
= 1 + iθ + + …… = eiθ and thus cos θ − i sin θ = e-iθ
