SOLUTION: Perform the indicated operation and express your answer in the form a + bi. sqrt{(4 + 3i)(3i - 4)}

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson -> SOLUTION: Perform the indicated operation and express your answer in the form a + bi. sqrt{(4 + 3i)(3i - 4)}      Log On


   



Question 1208826: Perform the indicated operation and express your answer in the form a + bi.

sqrt{(4 + 3i)(3i - 4)}

Answer by ikleyn(52803) About Me  (Show Source):
You can put this solution on YOUR website!
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Perform the indicated operation and express your answer in the form a + bi.
sqrt{(4 + 3i)(3i - 4)}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

(4 + 3i)*(3i - 4) = 4*3i - 4*4 +(3i)*(3i) - 3i*4 = 12i - 16 + 9i^2 - 12i = -16 + 9*(-1) = -16 - 9 = -25.


sqrt%28-25%29 = +/- 5i.


ANSWER.  sqrt%28%284%2B3i%29%2A%283i-4%29%29 = +/- 5i.


Thus  sqrt%28%284%2B3i%29%2A%283i-4%29%29  has two values:  one value is  5i  and  another value is  -5i.


In complete form a + bi,  first number is 0 + 5i;  the second number is 0 - 5i.


Do not be surprised: in complex domain, square root of non-zero number always has two values,
and these two values are opposite (have opposite signs).


The same as in the real domain for positive numbers.

Solved.