What is the plot of this implicit function: $|sin x|^y+|cos x|^y = 1$

The name of the pictureThe name of the pictureThe name of the pictureClash Royale CLAN TAG#URR8PPP











up vote
1
down vote

favorite












I'm trying to manually plot the following function:
$$
|sin x|^y+|cos x|^y = 1
$$
My basic approach for implicit functions is to try to express $y$ in terms of $x$ and plot it, or $x$ in terms of $y$ and then plot the inverse. Sometimes it's clear from the first glance if the equations is in some special form (for example a circumference).



For the above I couldn't find an explicit expression. I've tried to manipulate the expression in different ways in order to take logarithms and get rid of the $y$ power. It's even harder to get an insight since neither W|A nor desmos is able to plot it.



Below is the output from Mathematica which I don't really understand:



enter image description here




I'm interested in the ways I could transform the equation above so that it's easier to see what the graph looks like.




upd:



As pointed in the comments the above graph shows various contours. Below is the one which reflects the initial function:
enter image description here



Here is a Mathematica snippet for copy and paste:



ContourPlot[Abs[Cos[x]]^y + Abs[Sin[x]]^y == 1, x, -1, 1, y, -1, 10]


Just to be complete I'm adding the final plot from Mathematica (with some discrepancies which I assume are caused by the way Mathematica calculates the values) which reflects the answer by Michael Seifert.



final-plot







share|cite|improve this question





















  • Off-topic here, but to get the contour you're asking for in Mathematica, you need to have Abs[Cos[x]]^y + Abs[Sin[x]]^y - 1 == 0 (note the double equals sign.) As it is, Mathematica is plotting several contours of the function $f(x,y) = |sin x|^y+|cos x|^y - 1$, for various values of the contour.
    – Michael Seifert
    Aug 1 at 14:10










  • @MichaelSeifert Good point, didn't know that. I will update the OP with a new image
    – roman
    Aug 1 at 14:14










  • Also, you may need to zoom out a bit. I believe that no point of the contour lies in the range $-1<x<1$ and $-1<y<1$.
    – Michael Seifert
    Aug 1 at 14:15










  • @MichaelSeifert You are right no contour is indeed present in the range you pointed
    – roman
    Aug 1 at 14:24














up vote
1
down vote

favorite












I'm trying to manually plot the following function:
$$
|sin x|^y+|cos x|^y = 1
$$
My basic approach for implicit functions is to try to express $y$ in terms of $x$ and plot it, or $x$ in terms of $y$ and then plot the inverse. Sometimes it's clear from the first glance if the equations is in some special form (for example a circumference).



For the above I couldn't find an explicit expression. I've tried to manipulate the expression in different ways in order to take logarithms and get rid of the $y$ power. It's even harder to get an insight since neither W|A nor desmos is able to plot it.



Below is the output from Mathematica which I don't really understand:



enter image description here




I'm interested in the ways I could transform the equation above so that it's easier to see what the graph looks like.




upd:



As pointed in the comments the above graph shows various contours. Below is the one which reflects the initial function:
enter image description here



Here is a Mathematica snippet for copy and paste:



ContourPlot[Abs[Cos[x]]^y + Abs[Sin[x]]^y == 1, x, -1, 1, y, -1, 10]


Just to be complete I'm adding the final plot from Mathematica (with some discrepancies which I assume are caused by the way Mathematica calculates the values) which reflects the answer by Michael Seifert.



final-plot







share|cite|improve this question





















  • Off-topic here, but to get the contour you're asking for in Mathematica, you need to have Abs[Cos[x]]^y + Abs[Sin[x]]^y - 1 == 0 (note the double equals sign.) As it is, Mathematica is plotting several contours of the function $f(x,y) = |sin x|^y+|cos x|^y - 1$, for various values of the contour.
    – Michael Seifert
    Aug 1 at 14:10










  • @MichaelSeifert Good point, didn't know that. I will update the OP with a new image
    – roman
    Aug 1 at 14:14










  • Also, you may need to zoom out a bit. I believe that no point of the contour lies in the range $-1<x<1$ and $-1<y<1$.
    – Michael Seifert
    Aug 1 at 14:15










  • @MichaelSeifert You are right no contour is indeed present in the range you pointed
    – roman
    Aug 1 at 14:24












up vote
1
down vote

favorite









up vote
1
down vote

favorite











I'm trying to manually plot the following function:
$$
|sin x|^y+|cos x|^y = 1
$$
My basic approach for implicit functions is to try to express $y$ in terms of $x$ and plot it, or $x$ in terms of $y$ and then plot the inverse. Sometimes it's clear from the first glance if the equations is in some special form (for example a circumference).



For the above I couldn't find an explicit expression. I've tried to manipulate the expression in different ways in order to take logarithms and get rid of the $y$ power. It's even harder to get an insight since neither W|A nor desmos is able to plot it.



Below is the output from Mathematica which I don't really understand:



enter image description here




I'm interested in the ways I could transform the equation above so that it's easier to see what the graph looks like.




upd:



As pointed in the comments the above graph shows various contours. Below is the one which reflects the initial function:
enter image description here



Here is a Mathematica snippet for copy and paste:



ContourPlot[Abs[Cos[x]]^y + Abs[Sin[x]]^y == 1, x, -1, 1, y, -1, 10]


Just to be complete I'm adding the final plot from Mathematica (with some discrepancies which I assume are caused by the way Mathematica calculates the values) which reflects the answer by Michael Seifert.



final-plot







share|cite|improve this question













I'm trying to manually plot the following function:
$$
|sin x|^y+|cos x|^y = 1
$$
My basic approach for implicit functions is to try to express $y$ in terms of $x$ and plot it, or $x$ in terms of $y$ and then plot the inverse. Sometimes it's clear from the first glance if the equations is in some special form (for example a circumference).



For the above I couldn't find an explicit expression. I've tried to manipulate the expression in different ways in order to take logarithms and get rid of the $y$ power. It's even harder to get an insight since neither W|A nor desmos is able to plot it.



Below is the output from Mathematica which I don't really understand:



enter image description here




I'm interested in the ways I could transform the equation above so that it's easier to see what the graph looks like.




upd:



As pointed in the comments the above graph shows various contours. Below is the one which reflects the initial function:
enter image description here



Here is a Mathematica snippet for copy and paste:



ContourPlot[Abs[Cos[x]]^y + Abs[Sin[x]]^y == 1, x, -1, 1, y, -1, 10]


Just to be complete I'm adding the final plot from Mathematica (with some discrepancies which I assume are caused by the way Mathematica calculates the values) which reflects the answer by Michael Seifert.



final-plot









share|cite|improve this question












share|cite|improve this question




share|cite|improve this question








edited Aug 1 at 14:49
























asked Aug 1 at 13:52









roman

3941312




3941312











  • Off-topic here, but to get the contour you're asking for in Mathematica, you need to have Abs[Cos[x]]^y + Abs[Sin[x]]^y - 1 == 0 (note the double equals sign.) As it is, Mathematica is plotting several contours of the function $f(x,y) = |sin x|^y+|cos x|^y - 1$, for various values of the contour.
    – Michael Seifert
    Aug 1 at 14:10










  • @MichaelSeifert Good point, didn't know that. I will update the OP with a new image
    – roman
    Aug 1 at 14:14










  • Also, you may need to zoom out a bit. I believe that no point of the contour lies in the range $-1<x<1$ and $-1<y<1$.
    – Michael Seifert
    Aug 1 at 14:15










  • @MichaelSeifert You are right no contour is indeed present in the range you pointed
    – roman
    Aug 1 at 14:24
















  • Off-topic here, but to get the contour you're asking for in Mathematica, you need to have Abs[Cos[x]]^y + Abs[Sin[x]]^y - 1 == 0 (note the double equals sign.) As it is, Mathematica is plotting several contours of the function $f(x,y) = |sin x|^y+|cos x|^y - 1$, for various values of the contour.
    – Michael Seifert
    Aug 1 at 14:10










  • @MichaelSeifert Good point, didn't know that. I will update the OP with a new image
    – roman
    Aug 1 at 14:14










  • Also, you may need to zoom out a bit. I believe that no point of the contour lies in the range $-1<x<1$ and $-1<y<1$.
    – Michael Seifert
    Aug 1 at 14:15










  • @MichaelSeifert You are right no contour is indeed present in the range you pointed
    – roman
    Aug 1 at 14:24















Off-topic here, but to get the contour you're asking for in Mathematica, you need to have Abs[Cos[x]]^y + Abs[Sin[x]]^y - 1 == 0 (note the double equals sign.) As it is, Mathematica is plotting several contours of the function $f(x,y) = |sin x|^y+|cos x|^y - 1$, for various values of the contour.
– Michael Seifert
Aug 1 at 14:10




Off-topic here, but to get the contour you're asking for in Mathematica, you need to have Abs[Cos[x]]^y + Abs[Sin[x]]^y - 1 == 0 (note the double equals sign.) As it is, Mathematica is plotting several contours of the function $f(x,y) = |sin x|^y+|cos x|^y - 1$, for various values of the contour.
– Michael Seifert
Aug 1 at 14:10












@MichaelSeifert Good point, didn't know that. I will update the OP with a new image
– roman
Aug 1 at 14:14




@MichaelSeifert Good point, didn't know that. I will update the OP with a new image
– roman
Aug 1 at 14:14












Also, you may need to zoom out a bit. I believe that no point of the contour lies in the range $-1<x<1$ and $-1<y<1$.
– Michael Seifert
Aug 1 at 14:15




Also, you may need to zoom out a bit. I believe that no point of the contour lies in the range $-1<x<1$ and $-1<y<1$.
– Michael Seifert
Aug 1 at 14:15












@MichaelSeifert You are right no contour is indeed present in the range you pointed
– roman
Aug 1 at 14:24




@MichaelSeifert You are right no contour is indeed present in the range you pointed
– roman
Aug 1 at 14:24










1 Answer
1






active

oldest

votes

















up vote
2
down vote



accepted










We can see an obvious solution for the contour: if $y = 2$, we have $|cos x|^2 + |sin x|^2 = 1$, which is satisfied for all values of $x$. So the line $y = 2$ is part of the solution set.



If $y > 2$, then since $0leq |cos x| leq 1$, we have $|cos x|^y leq |cos x|^2$, with equality iff $|cos x| = 0$ or $|cos x| = 1$. A similar relation holds for $|sin x|$. Thus,
$$
|cos x|^y + |sin x|^y leq |cos x|^2 + |sin x|^2 = 1.
$$
Since equality only holds if both $|cos x|$ and $|sin x|$ are either 0 or 1, we cannot have $|cos x|^y + |sin x|^y = 1$ unless this is so. This occurs when $x = n pi/2$ for some integer $n$.



A similar argument can be made for when $y < 2$; in this case, we have $|cos x|^y geq |cos x|^2$ and similarly for $|sin x|$. Thus, $x = n pi/2$ is a solution when $y < 2$ as well. The only exception is that $0^0$ is indeterminate, so we cannot say that the points $x = n pi/2$, $y = 0$ are part of the contour.



Thus, the solution to the problem is the union of the sets $y = 2 $ and $x = npi/2, y neq 0$ for $n in mathbbZ$.






share|cite|improve this answer























  • You'll notice that the results from Mathematica aren't entirely accurate, since they miss the curves $x = n pi/2, y neq 0$ for $n neq 0$. If you're curious as to why this is, feel free to post a question over at Mathematica.SE.
    – Michael Seifert
    Aug 1 at 14:38











  • Now I see. I've just tried to play with $x$ and $y$ ranges after which your solutions absolutely makes sense, added the image to the OP. Thank you!
    – roman
    Aug 1 at 14:49










Your Answer




StackExchange.ifUsing("editor", function ()
return StackExchange.using("mathjaxEditing", function ()
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix)
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
);
);
, "mathjax-editing");

StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "69"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);

else
createEditor();

);

function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
convertImagesToLinks: true,
noModals: false,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);



);








 

draft saved


draft discarded


















StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2869092%2fwhat-is-the-plot-of-this-implicit-function-sin-xy-cos-xy-1%23new-answer', 'question_page');

);

Post as a guest






























1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
2
down vote



accepted










We can see an obvious solution for the contour: if $y = 2$, we have $|cos x|^2 + |sin x|^2 = 1$, which is satisfied for all values of $x$. So the line $y = 2$ is part of the solution set.



If $y > 2$, then since $0leq |cos x| leq 1$, we have $|cos x|^y leq |cos x|^2$, with equality iff $|cos x| = 0$ or $|cos x| = 1$. A similar relation holds for $|sin x|$. Thus,
$$
|cos x|^y + |sin x|^y leq |cos x|^2 + |sin x|^2 = 1.
$$
Since equality only holds if both $|cos x|$ and $|sin x|$ are either 0 or 1, we cannot have $|cos x|^y + |sin x|^y = 1$ unless this is so. This occurs when $x = n pi/2$ for some integer $n$.



A similar argument can be made for when $y < 2$; in this case, we have $|cos x|^y geq |cos x|^2$ and similarly for $|sin x|$. Thus, $x = n pi/2$ is a solution when $y < 2$ as well. The only exception is that $0^0$ is indeterminate, so we cannot say that the points $x = n pi/2$, $y = 0$ are part of the contour.



Thus, the solution to the problem is the union of the sets $y = 2 $ and $x = npi/2, y neq 0$ for $n in mathbbZ$.






share|cite|improve this answer























  • You'll notice that the results from Mathematica aren't entirely accurate, since they miss the curves $x = n pi/2, y neq 0$ for $n neq 0$. If you're curious as to why this is, feel free to post a question over at Mathematica.SE.
    – Michael Seifert
    Aug 1 at 14:38











  • Now I see. I've just tried to play with $x$ and $y$ ranges after which your solutions absolutely makes sense, added the image to the OP. Thank you!
    – roman
    Aug 1 at 14:49














up vote
2
down vote



accepted










We can see an obvious solution for the contour: if $y = 2$, we have $|cos x|^2 + |sin x|^2 = 1$, which is satisfied for all values of $x$. So the line $y = 2$ is part of the solution set.



If $y > 2$, then since $0leq |cos x| leq 1$, we have $|cos x|^y leq |cos x|^2$, with equality iff $|cos x| = 0$ or $|cos x| = 1$. A similar relation holds for $|sin x|$. Thus,
$$
|cos x|^y + |sin x|^y leq |cos x|^2 + |sin x|^2 = 1.
$$
Since equality only holds if both $|cos x|$ and $|sin x|$ are either 0 or 1, we cannot have $|cos x|^y + |sin x|^y = 1$ unless this is so. This occurs when $x = n pi/2$ for some integer $n$.



A similar argument can be made for when $y < 2$; in this case, we have $|cos x|^y geq |cos x|^2$ and similarly for $|sin x|$. Thus, $x = n pi/2$ is a solution when $y < 2$ as well. The only exception is that $0^0$ is indeterminate, so we cannot say that the points $x = n pi/2$, $y = 0$ are part of the contour.



Thus, the solution to the problem is the union of the sets $y = 2 $ and $x = npi/2, y neq 0$ for $n in mathbbZ$.






share|cite|improve this answer























  • You'll notice that the results from Mathematica aren't entirely accurate, since they miss the curves $x = n pi/2, y neq 0$ for $n neq 0$. If you're curious as to why this is, feel free to post a question over at Mathematica.SE.
    – Michael Seifert
    Aug 1 at 14:38











  • Now I see. I've just tried to play with $x$ and $y$ ranges after which your solutions absolutely makes sense, added the image to the OP. Thank you!
    – roman
    Aug 1 at 14:49












up vote
2
down vote



accepted







up vote
2
down vote



accepted






We can see an obvious solution for the contour: if $y = 2$, we have $|cos x|^2 + |sin x|^2 = 1$, which is satisfied for all values of $x$. So the line $y = 2$ is part of the solution set.



If $y > 2$, then since $0leq |cos x| leq 1$, we have $|cos x|^y leq |cos x|^2$, with equality iff $|cos x| = 0$ or $|cos x| = 1$. A similar relation holds for $|sin x|$. Thus,
$$
|cos x|^y + |sin x|^y leq |cos x|^2 + |sin x|^2 = 1.
$$
Since equality only holds if both $|cos x|$ and $|sin x|$ are either 0 or 1, we cannot have $|cos x|^y + |sin x|^y = 1$ unless this is so. This occurs when $x = n pi/2$ for some integer $n$.



A similar argument can be made for when $y < 2$; in this case, we have $|cos x|^y geq |cos x|^2$ and similarly for $|sin x|$. Thus, $x = n pi/2$ is a solution when $y < 2$ as well. The only exception is that $0^0$ is indeterminate, so we cannot say that the points $x = n pi/2$, $y = 0$ are part of the contour.



Thus, the solution to the problem is the union of the sets $y = 2 $ and $x = npi/2, y neq 0$ for $n in mathbbZ$.






share|cite|improve this answer















We can see an obvious solution for the contour: if $y = 2$, we have $|cos x|^2 + |sin x|^2 = 1$, which is satisfied for all values of $x$. So the line $y = 2$ is part of the solution set.



If $y > 2$, then since $0leq |cos x| leq 1$, we have $|cos x|^y leq |cos x|^2$, with equality iff $|cos x| = 0$ or $|cos x| = 1$. A similar relation holds for $|sin x|$. Thus,
$$
|cos x|^y + |sin x|^y leq |cos x|^2 + |sin x|^2 = 1.
$$
Since equality only holds if both $|cos x|$ and $|sin x|$ are either 0 or 1, we cannot have $|cos x|^y + |sin x|^y = 1$ unless this is so. This occurs when $x = n pi/2$ for some integer $n$.



A similar argument can be made for when $y < 2$; in this case, we have $|cos x|^y geq |cos x|^2$ and similarly for $|sin x|$. Thus, $x = n pi/2$ is a solution when $y < 2$ as well. The only exception is that $0^0$ is indeterminate, so we cannot say that the points $x = n pi/2$, $y = 0$ are part of the contour.



Thus, the solution to the problem is the union of the sets $y = 2 $ and $x = npi/2, y neq 0$ for $n in mathbbZ$.







share|cite|improve this answer















share|cite|improve this answer



share|cite|improve this answer








edited Aug 1 at 14:56


























answered Aug 1 at 14:36









Michael Seifert

4,449623




4,449623











  • You'll notice that the results from Mathematica aren't entirely accurate, since they miss the curves $x = n pi/2, y neq 0$ for $n neq 0$. If you're curious as to why this is, feel free to post a question over at Mathematica.SE.
    – Michael Seifert
    Aug 1 at 14:38











  • Now I see. I've just tried to play with $x$ and $y$ ranges after which your solutions absolutely makes sense, added the image to the OP. Thank you!
    – roman
    Aug 1 at 14:49
















  • You'll notice that the results from Mathematica aren't entirely accurate, since they miss the curves $x = n pi/2, y neq 0$ for $n neq 0$. If you're curious as to why this is, feel free to post a question over at Mathematica.SE.
    – Michael Seifert
    Aug 1 at 14:38











  • Now I see. I've just tried to play with $x$ and $y$ ranges after which your solutions absolutely makes sense, added the image to the OP. Thank you!
    – roman
    Aug 1 at 14:49















You'll notice that the results from Mathematica aren't entirely accurate, since they miss the curves $x = n pi/2, y neq 0$ for $n neq 0$. If you're curious as to why this is, feel free to post a question over at Mathematica.SE.
– Michael Seifert
Aug 1 at 14:38





You'll notice that the results from Mathematica aren't entirely accurate, since they miss the curves $x = n pi/2, y neq 0$ for $n neq 0$. If you're curious as to why this is, feel free to post a question over at Mathematica.SE.
– Michael Seifert
Aug 1 at 14:38













Now I see. I've just tried to play with $x$ and $y$ ranges after which your solutions absolutely makes sense, added the image to the OP. Thank you!
– roman
Aug 1 at 14:49




Now I see. I've just tried to play with $x$ and $y$ ranges after which your solutions absolutely makes sense, added the image to the OP. Thank you!
– roman
Aug 1 at 14:49












 

draft saved


draft discarded


























 


draft saved


draft discarded














StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2869092%2fwhat-is-the-plot-of-this-implicit-function-sin-xy-cos-xy-1%23new-answer', 'question_page');

);

Post as a guest













































































Comments

Popular posts from this blog

What is the equation of a 3D cone with generalised tilt?

Color the edges and diagonals of a regular polygon

Relationship between determinant of matrix and determinant of adjoint?