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Offline Seçkin USLU  
#1 Posted : 16 July 2019 08:57:05(UTC)
Seçkin USLU

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Hi all

İ have an equation like r(x)=1-x^2.

İs it possible to find max value of function.

Regards

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Offline Razonar  
#2 Posted : 16 July 2019 12:19:02(UTC)
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Hi Seçkin. Some notes about finding maxs.

maximun.sm (20kb) downloaded 155 time(s).

Best regards.
Alvaro.
thanks 1 user thanked Razonar for this useful post.
on 16/07/2019(UTC)
Offline Seçkin USLU  
#3 Posted : 16 July 2019 13:06:20(UTC)
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Hi Ronazar thanks for your answer.

İs it possible to find inverse of max value

For example f(5)=2 ise inverse of 2 equals 5

Thanks
Offline Jean Giraud  
#4 Posted : 16 July 2019 15:08:32(UTC)
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Originally Posted by: Seç Go to Quoted Post
Ä°s it possible to find max value of function.

The derivative method is just a quick lazy approach for convenience.
Derivative operator is symbolic, thus won't work for spline interpolation.
The min/max general method is the Golden Ratio.
You are confused with your next question "inverse"
An InverseFunction is a function that solve the given f(x)
... in preparation
Visit Golden ration posted next few minutes

Cheers.
Offline Jean Giraud  
#5 Posted : 16 July 2019 15:32:39(UTC)
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Originally Posted by: Seç Go to Quoted Post
Ä°s it possible to find inverse of max value
For example f(5)=2 ise inverse of 2 equals 5

... Sorry: don't understand your maths in there.
1. Understand InverseFunction
2. ISA altitude as superb application [won't find in Web]

Solve Inverse Symbolic Suite.sm (94kb) downloaded 24 time(s).
Inst_ISA [Landing altitude PDF].sm (306kb) downloaded 18 time(s).

Offline Razonar  
#6 Posted : 17 July 2019 03:10:27(UTC)
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Originally Posted by: Seç Go to Quoted Post
Hi Ronazar thanks for your answer.

İs it possible to find inverse of max value

For example f(5)=2 ise inverse of 2 equals 5

Thanks


Hi. If you have a max of y=2 that happen for x=5, then you can't invert y=f(x) near x=5, because then x=5 it's a critical point, then you have f'(5)=0, or a limit of the interval or a discontinuity, and the inverse function theorem it's a local theorem and needs f'(x)≠0 in the study interval.

Notice that the inverse function theorem it's easy to see graphically (the function isn't one to one), but very hard to demonstrate, as you can see at: http://people.math.sc.ed...p/InversefunctionThm.pdf

Best regards.
Alvaro.


Offline Jean Giraud  
#7 Posted : 17 July 2019 04:33:16(UTC)
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Revisit your example. The mechanics of Inversing a function is intuitive.
However the maths under the hood belongs to few advanced CAS [Maple World top].
Mathematica will do same, most of the times of different presentation.
Before you do anything with a function => graph.
Please, do not hesitate for more.

InverseFunction.PNG
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