The symbol **e ^{iθ}** or

**exp (iθ)**(called exponential of iθ) is defined by

**e ^{iθ} = cos θ + i sin θ**

This relation is known as **Euler’s formula**.

**z = r(cos θ + i sin θ) = re ^{iθ}**

This is called the exponential form of the complex number z.

The symbol **e ^{iθ}** or

**e ^{iθ} = cos θ + i sin θ**

This relation is known as **Euler’s formula**.

**z = r(cos θ + i sin θ) = re ^{iθ}**

This is called the exponential form of the complex number z.