Yes, 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.
Ronald
2012-10-26 23:12:28
Wait a minute,1/2(sqrt(5)-1) and sqrt(1.25)-.5 is same!
bobbym
2012-10-26 22:05:51
Please check your work I am not getting that. For one root I am getting.
That is what you wanted to show.
Ronald
2012-10-26 21:56:47
Sorry it is (sqrt(sqrt(1.25)-.5))
Ronald
2012-10-26 21:55:21
I get acos(sqrt(sqrt(1.25)-1)),so?
bobbym
2012-10-26 21:02:56
Hi Ronald;
You make the substitution y = cos(x) and then solve.
Another substitution, u=y^2.
Now it is easy.
Ronald
2012-10-26 20:54:41
During class I faced a problem- cos^4(x)+cos^2(x)=1,my friend told me that x=acos(sqrt(phi-1)).when I checked it using calculator,it was correct.how is phi involved in this,please explain.