■ You can enter **complex numbers** in **standard** form, a + bi, or use the **cis** function to enter **complex numbers** in **polar** form, r**cis**(θ) which stands for r(cos(θ) + **i** sin(θ)) which is equal to re**i**θ.

■ If the result of a calculation is a **complex number**, it is automatically displayed in **standard** form and **cis** form (and its equivalent **exponential** form).

Warning: In **Degree** mode, you may get unexpected erroneous results if the **argument** of the **non-algebraic** functions you use in your expressions is **not** a **purely real** or **purely imaginary** number. Use **Degrees** with discretion when *calculating* **complex number**.