Function plot limits produces errors

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Gavin Seddon
Gavin Seddon on 21 Jun 2016
Answered: the cyclist on 21 Jun 2016
fplot (@(x) was used to generate a figure the resulting curve shape is wrong and errors are produced. The correct X minimum and maximum values were not represented correctly. my command Used was taken from the 'help' menu. The errors were
>> fplot (@(x) (1211*x^6)/2500 + (9953*x^5)/10000 + (193*x^4)/125 - (681*x^3)/200 - (9549*x^2)/10000 + (3117*x)/1000 + 304/25, [0, 40000])
Warning: Function fails on array inputs. Use element-wise operators to increase speed.
> In matlab.graphics.function.FunctionLine>getFunction
In matlab.graphics.function.FunctionLine/set.Function_I
In matlab.graphics.function.FunctionLine/set.Function
In matlab.graphics.function.FunctionLine
In fplot>singleFplot (line 223)
In fplot>@(f)singleFplot(cax,{f},limits,extraOpts,args) (line 182)
In fplot>vectorizeFplot (line 182)
In fplot (line 153)
is the error with my limits? Can anyone help? G.
  1 Comment
Karan Gill
Karan Gill on 21 Jun 2016
Your command works fine for me. Can you explain why the resulting curve is wrong? I don't see an error in your output -- only a warning.

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Accepted Answer

the cyclist
the cyclist on 21 Jun 2016
You are getting that warning because you are using array multiplication in your function. Try this instead:
fplot (@(x) (1211*x.^6)/2500 + (9953*x.^5)/10000 + (193*x.^4)/125 - (681*x.^3)/200 - (9549*x.^2)/10000 + (3117*x)/1000 + 304/25, [0, 40000])
Note that I used element-wise multiplication in the function.

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