We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive pseudonymised information about your use of our website. cookie policy and privacy policy.
 
+0  
 
0
53
2
avatar

solve z^2 = 21 - 20i.

 Oct 29, 2019
 #1
avatar
0

Solve for z:
z^2 = 21 - 20 i

Take the square root of both sides:
z = sqrt(21 - 20 i) or z = -sqrt(21 - 20 i)

21 - 20 i = 25 - 20 i - 4 = 25 - 20 i + 4 i^2 = (-2 i + 5)^2:
z = 5 - 2 i or z = -sqrt(21 - 20 i)

21 - 20 i = 25 - 20 i - 4 = 25 - 20 i + 4 i^2 = (-2 i + 5)^2:
 
z = 5 - 2 i       or       z = -5 - 2 i

 Oct 29, 2019
 #2
avatar+105674 
0

Thanks guest. I had forgotten how to do that.

So at the very least you have refreshed my memory.

 Oct 31, 2019

32 Online Users

avatar
avatar