The problem is that Sage returns only one valua when solving sin(x)==0 and only one value, when solving cos(x) ==0. This makes only two valuaes for equation like sin(x)*cos(x) == 0 which is similar to your derivative.
You will have problems with solving f'(x)==0 if the derivative f'(x) is too complicated. In such a case you can find global min/max numerically. Robert On 8 bře, 17:50, Mike Brown <[email protected]> wrote: > Hi Marshall, > > Thank you for replaying. I do realize that this could probably be > done by hand. It is the easiest funcation that I have. But I wanted > to start with this one to get my feet wet. I have much bigger ones > like the Ackley function. > > I am trying to get my head around what sage is producing. There are > an infinate number of optima for f=(sin(5*pi*x))^6. Sage is producing > only two values. I would think that part of solving this using sage > is to limit x to values between 0 and 1. I believe that for > f=(sin(5*pi*x))^6 there are 5 or 6 maximums and 5 or 6 miniums for x > values between 0 and 1. So, what is [x == 0, x == (1/10)]? > > Thanks > Mike > > On Mar 8, 7:50 am, Marshall Hampton <[email protected]> wrote: > > > That particular example is almost easier to do by hand, but one way in > > Sage is: > > > f=(sin(5*pi*x))^6 > > solve(diff(f,x)==0,x) > > > which gives > > > [x == 0, x == (1/10)] > > > Of course there are a lot more solutions than those in this case; > > those might have been chosen by taking one branch of the inverse > > sine. > > > -M.Hampton > > > On Mar 7, 2:47 pm, Mike Brown <[email protected]> wrote: > > > > Hello, > > > > I want to say that I just learned about Sage. I tried installing it, > > > but I didn’t have enough memory and then I saw that I could run it > > > online. Impressive! What it can do is amazing. > > > > I have been playing around with sage and reading the documentation. I > > > am trying to find the local maximums for some continuous functions for > > > define domain ranges. I tried taking the derivative and finding out > > > where it is 0. That would tell me the local min and maxs. Then I was > > > going to figure out which ones are the local maxs. > > > > Here is one of the equations: f(x) = (sin (5*PI*x))^6, where 0 <= x > > > <=1. I am trying to find out what are the local maximums of that > > > equation. Can someone point me in the right direction? Can sage do > > > that directly? Is there a way to set the domain (ie 0 <= x <=1)? Any > > > help is greatly appreciated. > > > > Thanks > > > Mike Brown- Hide quoted text - > > > - Show quoted text - -- To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
