Answer with Step-by-step explanation:
We have to prove that
[tex]sin 2\theta=2sin\theta cos\theta[/tex] by using Euler's formula
Euler's formula :[tex]e^{i\theta}=cos\theta+isin\theta[/tex]
[tex]e^{i(2\theta)}=(e^{i\theta})^2[/tex]
By using Euler's identity, we get
[tex]cos2\theta+isin2\theta=(cos\theta+isin\theta)^2[/tex]
[tex]cos2\theta+isin2\theta=(cos^2\theta-sin^2\theta+2isin\theta cos\theta)[/tex]
[tex](a+b)^2=a^2+b^2+2ab, i^2=-1[/tex]
[tex]cos2\theta+isin2\theta=cos2\theta+i(2sin\theta cos\theta)[/tex]
[tex]cos2\theta=cos^2\theta-sin^2\theta[/tex]
Comparing imaginary part on both sides
Then, we get
[tex]sin2\theta=2sin\theta cos\theta[/tex]
Hence, proved.