SOLUTION: find absolute value of each complex number 2+4i= /4+16 /20= 2/5 my question is how it became from square root of/20 to 2/5?

Question 1151806: find absolute value of each complex number
2+4i=
/4+16
/20= 2/5
my question is how it became from square root of/20 to 2/5?
Found 3 solutions by MathLover1, MathTherapy, ikleyn:
Answer by MathLover1(20850)   (Show Source): You can put this solution on YOUR website!
find absolute value of each complex number=> I see one,
2+4i=
/4+16.....??????????????
/20= 2/5??????????????-> did you try to solve this

The absolute value of a real number like is its distance from on the number line.
The absolute value of complex number is also a measure of its distance from zero. However, instead of measuring this distance on the number line, a complex number's absolute value is measured on the complex number plane.
given:
If you think of the 'length' of as the from the to the point (,) then all you need is Pythagoras' Theorem;
in your example , where ,,you need the distance from (,) to (,) which is :

so, absolute value of is => your answer

Answer by MathTherapy(10552)   (Show Source): You can put this solution on YOUR website!
find absolute value of each complex number
2+4i=
/4+16
/20= 2/5
my question is how it became from square root of/20 to 2/5?

/4 + 16 <===== This is actually , which YOU should've written as: sqrt(4 + 16)
/20 <========= This is actually which shoudld've been written as sqrt(20)
2/5 <========= This is actually , which YOU should've written as 2sqrt(5)
You CANNOT use "/" in place of the square root symbol!
Answer by ikleyn(52792)   (Show Source): You can put this solution on YOUR website!
.

On complex numbers, see introductory lessons
    - Complex numbers and arithmetical operations on them
    - Complex plane
    - Addition and subtraction of complex numbers in complex plane
    - Multiplication and division of complex numbers in complex plane

    - Solved problems on taking roots of complex numbers
    - Solved problems on arithmetic operations on complex numbers
    - Solved problem on taking square root of complex number
in this site.

Also, you have this free of charge online textbook in ALGEBRA-II in this site
    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this online textbook under the topic "Complex numbers".

Save the link to this textbook together with its description

Free of charge online textbook in ALGEBRA-II
https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson

into your archive and use when it is needed.

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