Can somebody explain complex number to me? For example these kinds of problems: Is 5i a solution to 6= x(squared) +23

1 Answer
MattyMatty
Mar 8, 2018

#"See explanation"#

Explanation:

#i" is a number with the property that "i^2 = -1.#
#"So if you fill in "5i", you will get"#
#(5 i)^2 + 23 = 25 i^2 + 23 = 25 * -1 + 23 = -2 != 6#
#"So "5 i" is not a solution."#
#"Adding and multiplying with "i" goes just like with normal"#
#"real numbers, you just need to remember that "i^2 = -1.#
#"An odd power of "i" cannot be converted to a real number :"#
#"(5 i)^3 = 125 * i^3 = 125 * i^2 * i = 125 * -1 * i = -125 i.#
#"So then the imaginary unit "i" remains."#

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