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You are not logged in. #1 20121026 20:54:41
Phi in trigonometryDuring class I faced a problem cos^4(x)+cos^2(x)=1,my friend told me that x=acos(sqrt(phi1)).when I checked it using calculator,it was correct.how is phi involved in this,please explain. #2 20121026 21:02:56
Re: Phi in trigonometryHi Ronald; Another substitution, u=y^2. Now it is easy. In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #5 20121026 22:05:51
Re: Phi in trigonometryPlease check your work I am not getting that. For one root I am getting. That is what you wanted to show. In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #7 20121027 00:26:51
Re: Phi in trigonometryYes, it is the same but there is no reason to convert to decimal. You should avoid unnecessary simplifications. The way it is done in post #5 is fine. In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. 