Find the values of A in the range between 0 and 2pi for which sinA+sin3A=cosA+cos3A I have been trying for two days and still can't get it yet. Any help is greatly appreciated.
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Originally Posted by arze Find the values of A in the range between 0 and 2pi for which sinA+sin3A=cosA+cos3A I have been trying for two days and still can't get it yet. Any help is greatly appreciated. [edited from yeongil's post] Possible values
Last edited by great_math; July 9th 2009 at 12:36 AM. Reason: Made corrections
Originally Posted by great_math It's not a good idea to divide both sides by cos A like that. You lose roots that way. Instead, do this: Then proceed as in the previous post. 01
Originally Posted by yeongil It's not a good idea to divide both sides by cos A like that. You lose roots that way. Instead, do this: Then proceed as in the previous post. 01 Oops! I keep making that mistake again and again ....
Thank you so much!
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