How to determine local extrema for $f(x) = xcdot sin(x) ^ {sin(x)}$












2














I need to find the local extrema points of the following function:
$f(x) = xcdotsin(x) ^ {sin(x)}$



I was already able to derive to this function:
$f'(x) = x (ln(sin(x))+1)cos(x)sin(x)^{sin(x)}+sin(x)^ {sin(x)}$










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  • find $x$ where $f'(x)$ is equal to $0$. Then assess the sign change while crossing the roots
    – Makina
    Nov 23 at 19:45












  • This function is defined in $bigcuplimits_{ninmathbb Z}[2npi,2npi+pi]$.
    – Federico
    Nov 23 at 19:50










  • You first have to take into considerations the extreme points of the intervals
    – Federico
    Nov 23 at 19:51










  • Then your equation $f'=0$ inside these intervals is highly non-linear and trascendental...
    – Federico
    Nov 23 at 19:52










  • I don't think much can be said, except numerically
    – Federico
    Nov 23 at 19:53
















2














I need to find the local extrema points of the following function:
$f(x) = xcdotsin(x) ^ {sin(x)}$



I was already able to derive to this function:
$f'(x) = x (ln(sin(x))+1)cos(x)sin(x)^{sin(x)}+sin(x)^ {sin(x)}$










share|cite|improve this question
























  • find $x$ where $f'(x)$ is equal to $0$. Then assess the sign change while crossing the roots
    – Makina
    Nov 23 at 19:45












  • This function is defined in $bigcuplimits_{ninmathbb Z}[2npi,2npi+pi]$.
    – Federico
    Nov 23 at 19:50










  • You first have to take into considerations the extreme points of the intervals
    – Federico
    Nov 23 at 19:51










  • Then your equation $f'=0$ inside these intervals is highly non-linear and trascendental...
    – Federico
    Nov 23 at 19:52










  • I don't think much can be said, except numerically
    – Federico
    Nov 23 at 19:53














2












2








2







I need to find the local extrema points of the following function:
$f(x) = xcdotsin(x) ^ {sin(x)}$



I was already able to derive to this function:
$f'(x) = x (ln(sin(x))+1)cos(x)sin(x)^{sin(x)}+sin(x)^ {sin(x)}$










share|cite|improve this question















I need to find the local extrema points of the following function:
$f(x) = xcdotsin(x) ^ {sin(x)}$



I was already able to derive to this function:
$f'(x) = x (ln(sin(x))+1)cos(x)sin(x)^{sin(x)}+sin(x)^ {sin(x)}$







calculus derivatives trigonometry maxima-minima






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share|cite|improve this question













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share|cite|improve this question








edited Nov 23 at 20:02









David G. Stork

9,65121232




9,65121232










asked Nov 23 at 19:40









Phins

132




132












  • find $x$ where $f'(x)$ is equal to $0$. Then assess the sign change while crossing the roots
    – Makina
    Nov 23 at 19:45












  • This function is defined in $bigcuplimits_{ninmathbb Z}[2npi,2npi+pi]$.
    – Federico
    Nov 23 at 19:50










  • You first have to take into considerations the extreme points of the intervals
    – Federico
    Nov 23 at 19:51










  • Then your equation $f'=0$ inside these intervals is highly non-linear and trascendental...
    – Federico
    Nov 23 at 19:52










  • I don't think much can be said, except numerically
    – Federico
    Nov 23 at 19:53


















  • find $x$ where $f'(x)$ is equal to $0$. Then assess the sign change while crossing the roots
    – Makina
    Nov 23 at 19:45












  • This function is defined in $bigcuplimits_{ninmathbb Z}[2npi,2npi+pi]$.
    – Federico
    Nov 23 at 19:50










  • You first have to take into considerations the extreme points of the intervals
    – Federico
    Nov 23 at 19:51










  • Then your equation $f'=0$ inside these intervals is highly non-linear and trascendental...
    – Federico
    Nov 23 at 19:52










  • I don't think much can be said, except numerically
    – Federico
    Nov 23 at 19:53
















find $x$ where $f'(x)$ is equal to $0$. Then assess the sign change while crossing the roots
– Makina
Nov 23 at 19:45






find $x$ where $f'(x)$ is equal to $0$. Then assess the sign change while crossing the roots
– Makina
Nov 23 at 19:45














This function is defined in $bigcuplimits_{ninmathbb Z}[2npi,2npi+pi]$.
– Federico
Nov 23 at 19:50




This function is defined in $bigcuplimits_{ninmathbb Z}[2npi,2npi+pi]$.
– Federico
Nov 23 at 19:50












You first have to take into considerations the extreme points of the intervals
– Federico
Nov 23 at 19:51




You first have to take into considerations the extreme points of the intervals
– Federico
Nov 23 at 19:51












Then your equation $f'=0$ inside these intervals is highly non-linear and trascendental...
– Federico
Nov 23 at 19:52




Then your equation $f'=0$ inside these intervals is highly non-linear and trascendental...
– Federico
Nov 23 at 19:52












I don't think much can be said, except numerically
– Federico
Nov 23 at 19:53




I don't think much can be said, except numerically
– Federico
Nov 23 at 19:53










1 Answer
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The domain of $f$ is where $sin x>0$ i.e. $$bigcup_{nin Bbb Z}(2npi ,2npi +pi)$$ on this domain by equaling the derivative to zero we obtain $$sin x^{sin x}=0\text{or}\ x(1+ln sin x)cos x+1=0$$where $sin x^{sin x}=0$ is always impossible and the second equation can only be solved numerically. Here is a sketch of the functionenter image description here






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    1 Answer
    1






    active

    oldest

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    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    2














    The domain of $f$ is where $sin x>0$ i.e. $$bigcup_{nin Bbb Z}(2npi ,2npi +pi)$$ on this domain by equaling the derivative to zero we obtain $$sin x^{sin x}=0\text{or}\ x(1+ln sin x)cos x+1=0$$where $sin x^{sin x}=0$ is always impossible and the second equation can only be solved numerically. Here is a sketch of the functionenter image description here






    share|cite|improve this answer


























      2














      The domain of $f$ is where $sin x>0$ i.e. $$bigcup_{nin Bbb Z}(2npi ,2npi +pi)$$ on this domain by equaling the derivative to zero we obtain $$sin x^{sin x}=0\text{or}\ x(1+ln sin x)cos x+1=0$$where $sin x^{sin x}=0$ is always impossible and the second equation can only be solved numerically. Here is a sketch of the functionenter image description here






      share|cite|improve this answer
























        2












        2








        2






        The domain of $f$ is where $sin x>0$ i.e. $$bigcup_{nin Bbb Z}(2npi ,2npi +pi)$$ on this domain by equaling the derivative to zero we obtain $$sin x^{sin x}=0\text{or}\ x(1+ln sin x)cos x+1=0$$where $sin x^{sin x}=0$ is always impossible and the second equation can only be solved numerically. Here is a sketch of the functionenter image description here






        share|cite|improve this answer












        The domain of $f$ is where $sin x>0$ i.e. $$bigcup_{nin Bbb Z}(2npi ,2npi +pi)$$ on this domain by equaling the derivative to zero we obtain $$sin x^{sin x}=0\text{or}\ x(1+ln sin x)cos x+1=0$$where $sin x^{sin x}=0$ is always impossible and the second equation can only be solved numerically. Here is a sketch of the functionenter image description here







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Nov 23 at 20:19









        Mostafa Ayaz

        13.7k3836




        13.7k3836






























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