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One value of the square root is 2*(cos(10) + i*sin(10)).
The other value is 2*(-cos(10) - i*sin(10)), which is the opposite number to the first one.
There is a bunch of lessons on complex numbers
- 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
- Raising a complex number to an integer power
- How to take a root of a complex number (*)
- Solution of the quadratic equation with real coefficients on complex domain
- How to take a square root of a complex number (*)
- Solution of the quadratic equation with complex coefficients on complex domain
- 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.
From this list, the lessons marked by (*) specially relate to taking roots and square roots of complex numbers.
So, these lessons specially relate to your problem.
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".