Instructional Video
Khan Academy

Khan Academy: Algebra: Complex Numbers: I as the Principal Root of 1

9th - 10th
Video shows the logic behind why some believe that saying i is the principal root of -1 is wrong. Explains why the logic is faulty. Explains more technically the meaning of principal root. [6:44]
Instructional Video
Khan Academy

Khan Academy: Algebra: Complex Numbers

9th - 10th Standards
Video explains what complex numbers are and shows how to write them. Includes an example of writing a real number as a complex number. [2:21]
Instructional Video
Khan Academy

Khan Academy: The Imaginary Unit I: Calculating I Raised to Arbitrary Exponents

9th - 10th
Video shows how to write i raised to various powers as simpler problems using exponent rules.
Instructional Video
Khan Academy

Khan Academy: The Imaginary Unit I: I as the Principal Root of 1

9th - 10th
Video shows the logic behind why some believe that saying i is the principal root of -1 is wrong.
Instructional Video
Khan Academy

Khan Academy: Algebra: Complex Numbers: Imaginary Roots of Negative Numbers

9th - 10th Standards
Video shows how to simplify the square root of a negative number using the imaginary unit i. [4:04]
Instructional Video
Khan Academy

Khan Academy: The Imaginary Unit I: Imaginary Roots of Negative Numbers

9th - 10th Standards
Video shows how to simplify the square root of a negative number using the imaginary unit i.
Instructional Video
Khan Academy

Khan Academy: Algebra: Complex Numbers: Introduction to I and Imaginary Numbers

9th - 10th Standards
Video introduces i as the imaginary unit, gives two versions of the definition for i, and then shows what various powers of i equal. [5:20]