# [SOLVED] Two different complex answers

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• August 7th 2008, 04:41 AM
Evales
[SOLVED] Two different complex answers
When try to find a complex number in rectangular form there are two ways I do it.

A. Put it in exponential form and let my calculator do it.

B. Use:
$r cis x = r cos x + ir sin x$

Now with $\sqrt{3}cis3$ I get two different answers

A. -1.7147 + 0.2444i

B. 1.7297 + 0.0906i

Which is right? Is my rule for B wrong?
• August 7th 2008, 04:48 AM
mr fantastic
Quote:

Originally Posted by Evales
When try to find a complex number in rectangular form there are two ways I do it.

A. Put it in exponential form and let my calculator do it.

B. Use:
$r cis x = r cos x + ir sin x$

Now with $\sqrt{3}cis3$ I get two different answers

A. -1.7147 + 0.2444i

B. 1.7297 + 0.0906i

Which is right? Is my rule for B wrong?

A. is the correct answer.

You got the wrong answer using method B. because your calculator is in degree mode. It needs to be in radian mode.