# Question regarding complex numbers

1)If a= cosα + i sinα and the equation az2 + az +1 =0 has a pure imaginary root, then tanα=?

3) What i tried to do was,i put a constant real number and tried to solve it and used demoivres theorem, although the answer is getting weirder and weirder.

PeroK
Homework Helper
Gold Member
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You need to show your work.

Mark44
Mentor
You need to show your work.
Yes, please show what you have done, Mohsin Hussain.

This is an important piece of information --
the equation az2 + az +1 =0 has a pure imaginary root

sorry for bothering, it was a fairly easy one. didnt read the word "purely". Thanks.